From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Wed, 24 Jul 2013 16:03:53 +0000 (+0200)
Subject: lib: macro-ify type checks
X-Git-Tag: v0.11.5~73
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0330bdf5195eb77f04c26a09a8bd2088a261fe53;p=platform%2Fupstream%2Fnodejs.git

lib: macro-ify type checks

Increases the grep factor. Makes it easier to harmonize type checks
across the code base.
---

diff --git a/lib/_debugger.js b/lib/_debugger.js
index 10096b5..993fcba 100644
--- a/lib/_debugger.js
+++ b/lib/_debugger.js
@@ -182,7 +182,7 @@ exports.Client = Client;
 
 
 Client.prototype._addHandle = function(desc) {
-  if (typeof desc != 'object' || typeof desc.handle != 'number') {
+  if (!IS_OBJECT(desc) || !IS_NUMBER(desc.handle)) {
     return;
   }
 
@@ -296,7 +296,7 @@ Client.prototype.reqLookup = function(refs, cb) {
   this.req(req, function(err, res) {
     if (err) return cb(err);
     for (var ref in res) {
-      if (typeof res[ref] == 'object') {
+      if (IS_OBJECT(res[ref])) {
         self._addHandle(res[ref]);
       }
     }
@@ -559,8 +559,7 @@ Client.prototype.mirrorObject = function(handle, depth, cb) {
         }
 
 
-        if (Array.isArray(mirror) &&
-            typeof prop.name != 'number') {
+        if (IS_ARRAY(mirror) && !IS_NUMBER(prop.name)) {
           // Skip the 'length' property.
           return;
         }
@@ -593,7 +592,7 @@ Client.prototype.mirrorObject = function(handle, depth, cb) {
     val = function() {};
   } else if (handle.type === 'null') {
     val = null;
-  } else if (handle.value !== undefined) {
+  } else if (!IS_UNDEFINED(handle.value)) {
     val = handle.value;
   } else if (handle.type === 'undefined') {
     val = undefined;
@@ -892,7 +891,7 @@ Interface.prototype.print = function(text, oneline) {
   if (this.killed) return;
   this.clearline();
 
-  this.stdout.write(typeof text === 'string' ? text : util.inspect(text));
+  this.stdout.write(IS_STRING(text) ? text : util.inspect(text));
 
   if (oneline !== true) {
     this.stdout.write('\n');
@@ -1214,7 +1213,7 @@ Interface.prototype.scripts = function() {
   this.pause();
   for (var id in client.scripts) {
     var script = client.scripts[id];
-    if (typeof script == 'object' && script.name) {
+    if (IS_OBJECT(script) && script.name) {
       if (displayNatives ||
           script.name == client.currentScript ||
           !script.isNative) {
@@ -1351,13 +1350,13 @@ Interface.prototype.setBreakpoint = function(script, line,
       ambiguous;
 
   // setBreakpoint() should insert breakpoint on current line
-  if (script === undefined) {
+  if (IS_UNDEFINED(script)) {
     script = this.client.currentScript;
     line = this.client.currentSourceLine + 1;
   }
 
   // setBreakpoint(line-number) should insert breakpoint in current script
-  if (line === undefined && typeof script === 'number') {
+  if (IS_UNDEFINED(line) && IS_NUMBER(script)) {
     line = script;
     script = this.client.currentScript;
   }
@@ -1452,7 +1451,7 @@ Interface.prototype.clearBreakpoint = function(script, line) {
     if (bp.scriptId === script ||
         bp.scriptReq === script ||
         (bp.script && bp.script.indexOf(script) !== -1)) {
-      if (index !== undefined) {
+      if (!IS_UNDEFINED(index)) {
         ambiguous = true;
       }
       if (bp.line === line) {
@@ -1465,7 +1464,7 @@ Interface.prototype.clearBreakpoint = function(script, line) {
 
   if (ambiguous) return this.error('Script name is ambiguous');
 
-  if (breakpoint === undefined) {
+  if (IS_UNDEFINED(breakpoint)) {
     return this.error('Script : ' + script + ' not found');
   }
 
diff --git a/lib/_http_agent.js b/lib/_http_agent.js
index 07e8f4c..500ddb0 100644
--- a/lib/_http_agent.js
+++ b/lib/_http_agent.js
@@ -246,7 +246,7 @@ Agent.prototype.destroy = function() {
 };
 
 Agent.prototype.request = function(options, cb) {
-  if (typeof options === 'string') {
+  if (IS_STRING(options)) {
     options = url.parse(options);
   }
   // don't try to do dns lookups of foo.com:8080, just foo.com
diff --git a/lib/_http_client.js b/lib/_http_client.js
index 2af127c..ca82bf7 100644
--- a/lib/_http_client.js
+++ b/lib/_http_client.js
@@ -44,14 +44,14 @@ function ClientRequest(options, cb) {
   var self = this;
   OutgoingMessage.call(self);
 
-  self.agent = options.agent === undefined ? globalAgent : options.agent;
+  self.agent = IS_UNDEFINED(options.agent) ? globalAgent : options.agent;
 
   var defaultPort = options.defaultPort || 80;
 
   var port = options.port || defaultPort;
   var host = options.hostname || options.host || 'localhost';
 
-  if (options.setHost === undefined) {
+  if (IS_UNDEFINED(options.setHost)) {
     var setHost = true;
   }
 
@@ -63,7 +63,7 @@ function ClientRequest(options, cb) {
     self.once('response', cb);
   }
 
-  if (!Array.isArray(options.headers)) {
+  if (!IS_ARRAY(options.headers)) {
     if (options.headers) {
       var keys = Object.keys(options.headers);
       for (var i = 0, l = keys.length; i < l; i++) {
@@ -92,7 +92,7 @@ function ClientRequest(options, cb) {
     self.useChunkedEncodingByDefault = true;
   }
 
-  if (Array.isArray(options.headers)) {
+  if (IS_ARRAY(options.headers)) {
     self._storeHeader(self.method + ' ' + self.path + ' HTTP/1.1\r\n',
                       options.headers);
   } else if (self.getHeader('expect')) {
@@ -413,7 +413,7 @@ ClientRequest.prototype.onSocket = function(socket) {
     httpSocketSetup(socket);
 
     // Propagate headers limit from request object to parser
-    if (typeof req.maxHeadersCount === 'number') {
+    if (IS_NUMBER(req.maxHeadersCount)) {
       parser.maxHeaderPairs = req.maxHeadersCount << 1;
     } else {
       // Set default value because parser may be reused from FreeList
diff --git a/lib/_http_incoming.js b/lib/_http_incoming.js
index c089ec9..f11d098 100644
--- a/lib/_http_incoming.js
+++ b/lib/_http_incoming.js
@@ -125,7 +125,7 @@ IncomingMessage.prototype._addHeaderLine = function(field, value) {
   switch (field) {
     // Array headers:
     case 'set-cookie':
-      if (dest[field] !== undefined) {
+      if (!IS_UNDEFINED(dest[field])) {
         dest[field].push(value);
       } else {
         dest[field] = [value];
@@ -145,7 +145,7 @@ IncomingMessage.prototype._addHeaderLine = function(field, value) {
     case 'proxy-authenticate':
     case 'sec-websocket-extensions':
     case 'sec-websocket-protocol':
-      if (dest[field] !== undefined) {
+      if (!IS_UNDEFINED(dest[field])) {
         dest[field] += ', ' + value;
       } else {
         dest[field] = value;
@@ -156,14 +156,14 @@ IncomingMessage.prototype._addHeaderLine = function(field, value) {
     default:
       if (field.slice(0, 2) == 'x-') {
         // except for x-
-        if (dest[field] !== undefined) {
+        if (!IS_UNDEFINED(dest[field])) {
           dest[field] += ', ' + value;
         } else {
           dest[field] = value;
         }
       } else {
         // drop duplicates
-        if (dest[field] === undefined) dest[field] = value;
+        if (IS_UNDEFINED(dest[field])) dest[field] = value;
       }
       break;
   }
diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index 397b430..fd4681f 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -115,7 +115,7 @@ OutgoingMessage.prototype._send = function(data, encoding) {
   // the same packet. Future versions of Node are going to take care of
   // this at a lower level and in a more general way.
   if (!this._headerSent) {
-    if (typeof data === 'string') {
+    if (IS_STRING(data)) {
       data = this._header + data;
     } else {
       this.output.unshift(this._header);
@@ -166,7 +166,7 @@ OutgoingMessage.prototype._buffer = function(data, encoding) {
 
   var length = this.output.length;
 
-  if (length === 0 || typeof data != 'string') {
+  if (length === 0 || !IS_STRING(data)) {
     this.output.push(data);
     this.outputEncodings.push(encoding);
     return false;
@@ -205,7 +205,7 @@ OutgoingMessage.prototype._storeHeader = function(firstLine, headers) {
 
   if (headers) {
     var keys = Object.keys(headers);
-    var isArray = (Array.isArray(headers));
+    var isArray = IS_ARRAY(headers);
     var field, value;
 
     for (var i = 0, l = keys.length; i < l; i++) {
@@ -218,7 +218,7 @@ OutgoingMessage.prototype._storeHeader = function(firstLine, headers) {
         value = headers[key];
       }
 
-      if (Array.isArray(value)) {
+      if (IS_ARRAY(value)) {
         for (var j = 0; j < value.length; j++) {
           storeHeader(this, state, field, value[j]);
         }
@@ -401,7 +401,7 @@ OutgoingMessage.prototype.write = function(chunk, encoding) {
     return true;
   }
 
-  if (typeof chunk !== 'string' && !Buffer.isBuffer(chunk)) {
+  if (!IS_STRING(chunk) && !IS_BUFFER(chunk)) {
     throw new TypeError('first argument must be a string or Buffer');
   }
 
@@ -412,7 +412,7 @@ OutgoingMessage.prototype.write = function(chunk, encoding) {
 
   var len, ret;
   if (this.chunkedEncoding) {
-    if (typeof(chunk) === 'string' &&
+    if (IS_STRING(chunk) &&
         encoding !== 'hex' &&
         encoding !== 'base64' &&
         encoding !== 'binary') {
@@ -444,7 +444,7 @@ OutgoingMessage.prototype.write = function(chunk, encoding) {
 OutgoingMessage.prototype.addTrailers = function(headers) {
   this._trailer = '';
   var keys = Object.keys(headers);
-  var isArray = (Array.isArray(headers));
+  var isArray = IS_ARRAY(headers);
   var field, value;
   for (var i = 0, l = keys.length; i < l; i++) {
     var key = keys[i];
@@ -466,7 +466,7 @@ var crlf_buf = new Buffer('\r\n');
 
 
 OutgoingMessage.prototype.end = function(data, encoding) {
-  if (data && typeof data !== 'string' && !Buffer.isBuffer(data)) {
+  if (data && !IS_STRING(data) && !IS_BUFFER(data)) {
     throw new TypeError('first argument must be a string or Buffer');
   }
 
diff --git a/lib/_http_server.js b/lib/_http_server.js
index f6cfa35..4c7f92d 100644
--- a/lib/_http_server.js
+++ b/lib/_http_server.js
@@ -173,7 +173,7 @@ ServerResponse.prototype._implicitHeader = function() {
 ServerResponse.prototype.writeHead = function(statusCode) {
   var reasonPhrase, headers, headerIndex;
 
-  if (typeof arguments[1] == 'string') {
+  if (IS_STRING(arguments[1])) {
     reasonPhrase = arguments[1];
     headerIndex = 2;
   } else {
@@ -188,13 +188,13 @@ ServerResponse.prototype.writeHead = function(statusCode) {
     // Slow-case: when progressive API and header fields are passed.
     headers = this._renderHeaders();
 
-    if (Array.isArray(obj)) {
+    if (IS_ARRAY(obj)) {
       // handle array case
       // TODO: remove when array is no longer accepted
       var field;
       for (var i = 0, len = obj.length; i < len; ++i) {
         field = obj[i][0];
-        if (headers[field] !== undefined) {
+        if (!IS_UNDEFINED(headers[field])) {
           obj.push([field, headers[field]]);
         }
       }
@@ -332,7 +332,7 @@ function connectionListener(socket) {
   parser.incoming = null;
 
   // Propagate headers limit from server instance to parser
-  if (typeof this.maxHeadersCount === 'number') {
+  if (IS_NUMBER(this.maxHeadersCount)) {
     parser.maxHeaderPairs = this.maxHeadersCount << 1;
   } else {
     // Set default value because parser may be reused from FreeList
@@ -442,7 +442,7 @@ function connectionListener(socket) {
       }
     });
 
-    if (req.headers.expect !== undefined &&
+    if (!IS_UNDEFINED(req.headers.expect) &&
         (req.httpVersionMajor == 1 && req.httpVersionMinor == 1) &&
         continueExpression.test(req.headers['expect'])) {
       res._expect_continue = true;
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index c6f31bc..0b5af41 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -117,7 +117,7 @@ function Readable(options) {
 Readable.prototype.push = function(chunk, encoding) {
   var state = this._readableState;
 
-  if (typeof chunk === 'string' && !state.objectMode) {
+  if (IS_STRING(chunk) && !state.objectMode) {
     encoding = encoding || state.defaultEncoding;
     if (encoding !== state.encoding) {
       chunk = new Buffer(chunk, encoding);
@@ -138,7 +138,7 @@ function readableAddChunk(stream, state, chunk, encoding, addToFront) {
   var er = chunkInvalid(state, chunk);
   if (er) {
     stream.emit('error', er);
-  } else if (chunk === null || chunk === undefined) {
+  } else if (IS_NULL_OR_UNDEFINED(chunk)) {
     state.reading = false;
     if (!state.ended)
       onEofChunk(stream, state);
@@ -219,7 +219,7 @@ function howMuchToRead(n, state) {
   if (state.objectMode)
     return n === 0 ? 0 : 1;
 
-  if (isNaN(n) || n === null) {
+  if (isNaN(n) || IS_NULL(n)) {
     // only flow one buffer at a time
     if (state.flowing && state.buffer.length)
       return state.buffer[0].length;
@@ -256,7 +256,7 @@ Readable.prototype.read = function(n) {
   state.calledRead = true;
   var nOrig = n;
 
-  if (typeof n !== 'number' || n > 0)
+  if (!IS_NUMBER(n) || n > 0)
     state.emittedReadable = false;
 
   // if we're doing read(0) to trigger a readable event, but we
@@ -345,7 +345,7 @@ Readable.prototype.read = function(n) {
   else
     ret = null;
 
-  if (ret === null) {
+  if (IS_NULL(ret)) {
     state.needReadable = true;
     n = 0;
   }
@@ -363,17 +363,16 @@ Readable.prototype.read = function(n) {
   if (state.ended && !state.endEmitted && state.length === 0)
     endReadable(this);
 
-  if (ret !== null)
+  if (!IS_NULL(ret))
     this.emit('data', ret);
   return ret;
 };
 
 function chunkInvalid(state, chunk) {
   var er = null;
-  if (!Buffer.isBuffer(chunk) &&
-      'string' !== typeof chunk &&
-      chunk !== null &&
-      chunk !== undefined &&
+  if (!IS_BUFFER(chunk) &&
+      !IS_STRING(chunk) &&
+      !IS_NULL_OR_UNDEFINED(chunk) &&
       !state.objectMode &&
       !er) {
     er = new TypeError('Invalid non-string/buffer chunk');
@@ -775,8 +774,7 @@ Readable.prototype.wrap = function(stream) {
   // proxy all the other methods.
   // important when wrapping filters and duplexes.
   for (var i in stream) {
-    if (typeof stream[i] === 'function' &&
-        typeof this[i] === 'undefined') {
+    if (IS_FUNCTION(stream[i]) && IS_UNDEFINED(this[i])) {
       this[i] = function(method) { return function() {
         return stream[method].apply(stream, arguments);
       }}(i);
diff --git a/lib/_stream_transform.js b/lib/_stream_transform.js
index f246ef7..735f2cf 100644
--- a/lib/_stream_transform.js
+++ b/lib/_stream_transform.js
@@ -92,7 +92,7 @@ function afterTransform(stream, er, data) {
   ts.writechunk = null;
   ts.writecb = null;
 
-  if (data !== null && data !== undefined)
+  if (!IS_NULL_OR_UNDEFINED(data))
     stream.push(data);
 
   if (cb)
@@ -126,7 +126,7 @@ function Transform(options) {
   this._readableState.sync = false;
 
   this.once('prefinish', function() {
-    if ('function' === typeof this._flush)
+    if (IS_FUNCTION(this._flush))
       this._flush(function(er) {
         done(stream, er);
       });
@@ -174,7 +174,7 @@ Transform.prototype._write = function(chunk, encoding, cb) {
 Transform.prototype._read = function(n) {
   var ts = this._transformState;
 
-  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
+  if (!IS_NULL(ts.writechunk) && ts.writecb && !ts.transforming) {
     ts.transforming = true;
     this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
   } else {
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index cada467..a6b02f6 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -153,10 +153,9 @@ function writeAfterEnd(stream, state, cb) {
 // how many bytes or characters.
 function validChunk(stream, state, chunk, cb) {
   var valid = true;
-  if (!Buffer.isBuffer(chunk) &&
-      'string' !== typeof chunk &&
-      chunk !== null &&
-      chunk !== undefined &&
+  if (!IS_BUFFER(chunk) &&
+      !IS_STRING(chunk) &&
+      !IS_NULL_OR_UNDEFINED(chunk) &&
       !state.objectMode) {
     var er = new TypeError('Invalid non-string/buffer chunk');
     stream.emit('error', er);
@@ -172,17 +171,17 @@ Writable.prototype.write = function(chunk, encoding, cb) {
   var state = this._writableState;
   var ret = false;
 
-  if (typeof encoding === 'function') {
+  if (IS_FUNCTION(encoding)) {
     cb = encoding;
     encoding = null;
   }
 
-  if (Buffer.isBuffer(chunk))
+  if (IS_BUFFER(chunk))
     encoding = 'buffer';
   else if (!encoding)
     encoding = state.defaultEncoding;
 
-  if (typeof cb !== 'function')
+  if (!IS_FUNCTION(cb))
     cb = function() {};
 
   if (state.ended)
@@ -217,9 +216,7 @@ Writable.prototype.uncork = function() {
 };
 
 function decodeChunk(state, chunk, encoding) {
-  if (!state.objectMode &&
-      state.decodeStrings !== false &&
-      typeof chunk === 'string') {
+  if (!state.objectMode && state.decodeStrings !== false && IS_STRING(chunk)) {
     chunk = new Buffer(chunk, encoding);
   }
   return chunk;
@@ -230,7 +227,7 @@ function decodeChunk(state, chunk, encoding) {
 // If we return false, then we need a drain event, so set that flag.
 function writeOrBuffer(stream, state, chunk, encoding, cb) {
   chunk = decodeChunk(state, chunk, encoding);
-  if (Buffer.isBuffer(chunk))
+  if (IS_BUFFER(chunk))
     encoding = 'buffer';
   var len = state.objectMode ? 1 : chunk.length;
 
@@ -391,16 +388,16 @@ Writable.prototype._writev = null;
 Writable.prototype.end = function(chunk, encoding, cb) {
   var state = this._writableState;
 
-  if (typeof chunk === 'function') {
+  if (IS_FUNCTION(chunk)) {
     cb = chunk;
     chunk = null;
     encoding = null;
-  } else if (typeof encoding === 'function') {
+  } else if (IS_FUNCTION(encoding)) {
     cb = encoding;
     encoding = null;
   }
 
-  if (typeof chunk !== 'undefined' && chunk !== null)
+  if (!IS_NULL_OR_UNDEFINED(chunk))
     this.write(chunk, encoding);
 
   // .end() fully uncorks
diff --git a/lib/_tls_legacy.js b/lib/_tls_legacy.js
index 4acabe3..6c85251 100644
--- a/lib/_tls_legacy.js
+++ b/lib/_tls_legacy.js
@@ -36,7 +36,7 @@ SlabBuffer.prototype.use = function use(context, fn, size) {
 
   var actualSize = this.remaining;
 
-  if (size !== null) actualSize = Math.min(size, actualSize);
+  if (!IS_NULL(size)) actualSize = Math.min(size, actualSize);
 
   var bytes = fn.call(context, this.pool, this.offset, actualSize);
   if (bytes > 0) {
@@ -72,7 +72,7 @@ function CryptoStream(pair, options) {
   this._finished = false;
   this._opposite = null;
 
-  if (slabBuffer === null) slabBuffer = new SlabBuffer();
+  if (IS_NULL(slabBuffer)) slabBuffer = new SlabBuffer();
   this._buffer = slabBuffer;
 
   this.once('finish', onCryptoStreamFinish);
@@ -144,7 +144,7 @@ CryptoStream.prototype.init = function init() {
 
 
 CryptoStream.prototype._write = function write(data, encoding, cb) {
-  assert(this._pending === null);
+  assert(IS_NULL(this._pending));
 
   // Black-hole data
   if (!this.pair.ssl) return cb(null);
@@ -191,7 +191,7 @@ CryptoStream.prototype._write = function write(data, encoding, cb) {
 
       // Invoke callback only when all data read from opposite stream
       if (this._opposite._halfRead) {
-        assert(this._sslOutCb === null);
+        assert(IS_NULL(this._sslOutCb));
         this._sslOutCb = cb;
       } else {
         cb(null);
@@ -285,8 +285,8 @@ CryptoStream.prototype._read = function read(size) {
   }
 
   // Try writing pending data
-  if (this._pending !== null) this._writePending();
-  if (this._opposite._pending !== null) this._opposite._writePending();
+  if (!IS_NULL(this._pending)) this._writePending();
+  if (!IS_NULL(this._opposite._pending)) this._opposite._writePending();
 
   if (bytesRead === 0) {
     // EOF when cleartext has finished and we have nothing to read
@@ -405,7 +405,7 @@ CryptoStream.prototype.end = function(chunk, encoding) {
   }
 
   // Write pending data first
-  if (this._pending !== null) this._writePending();
+  if (!IS_NULL(this._pending)) this._writePending();
 
   this.writable = false;
 
diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
index c6b0a3c..bdba9cf 100644
--- a/lib/_tls_wrap.js
+++ b/lib/_tls_wrap.js
@@ -207,7 +207,7 @@ TLSSocket.prototype.setServername = function(name) {
 };
 
 TLSSocket.prototype.setSession = function(session) {
-  if (typeof session === 'string')
+  if (IS_STRING(session))
     session = new Buffer(session, 'binary');
   this.ssl.setSession(session);
 };
@@ -319,10 +319,10 @@ TLSSocket.prototype.getCipher = function(err) {
 //
 function Server(/* [options], listener */) {
   var options, listener;
-  if (typeof arguments[0] == 'object') {
+  if (IS_OBJECT(arguments[0])) {
     options = arguments[0];
     listener = arguments[1];
-  } else if (typeof arguments[0] == 'function') {
+  } else if (IS_FUNCTION(arguments[0])) {
     options = {};
     listener = arguments[0];
   }
@@ -355,7 +355,7 @@ function Server(/* [options], listener */) {
 
   var timeout = options.handshakeTimeout || (120 * 1000);
 
-  if (typeof timeout !== 'number') {
+  if (!IS_NUMBER(timeout)) {
     throw new TypeError('handshakeTimeout must be a number');
   }
 
@@ -423,13 +423,13 @@ exports.createServer = function(options, listener) {
 
 
 Server.prototype.setOptions = function(options) {
-  if (typeof options.requestCert == 'boolean') {
+  if (IS_BOOLEAN(options.requestCert)) {
     this.requestCert = options.requestCert;
   } else {
     this.requestCert = false;
   }
 
-  if (typeof options.rejectUnauthorized == 'boolean') {
+  if (IS_BOOLEAN(options.rejectUnauthorized)) {
     this.rejectUnauthorized = options.rejectUnauthorized;
   } else {
     this.rejectUnauthorized = false;
@@ -481,7 +481,7 @@ Server.prototype.SNICallback = function(servername) {
   var ctx;
 
   this._contexts.some(function(elem) {
-    if (servername.match(elem[0]) !== null) {
+    if (!IS_NULL(servername.match(elem[0]))) {
       ctx = elem[1];
       return true;
     }
@@ -510,9 +510,9 @@ function normalizeConnectArgs(listArgs) {
   var options = args[0];
   var cb = args[1];
 
-  if (typeof listArgs[1] === 'object') {
+  if (IS_OBJECT(listArgs[1])) {
     options = util._extend(options, listArgs[1]);
-  } else if (typeof listArgs[2] === 'object') {
+  } else if (IS_OBJECT(listArgs[2])) {
     options = util._extend(options, listArgs[2]);
   }
 
diff --git a/lib/assert.js b/lib/assert.js
index 11fef45..fcd4886 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -51,20 +51,20 @@ assert.AssertionError = function AssertionError(options) {
 util.inherits(assert.AssertionError, Error);
 
 function replacer(key, value) {
-  if (value === undefined) {
+  if (IS_UNDEFINED(value)) {
     return '' + value;
   }
-  if (typeof value === 'number' && (isNaN(value) || !isFinite(value))) {
+  if (IS_NUMBER(value) && (isNaN(value) || !isFinite(value))) {
     return value.toString();
   }
-  if (typeof value === 'function' || value instanceof RegExp) {
+  if (IS_FUNCTION(value) || IS_REGEXP(value)) {
     return value.toString();
   }
   return value;
 }
 
 function truncate(s, n) {
-  if (typeof s == 'string') {
+  if (IS_STRING(s)) {
     return s.length < n ? s : s.slice(0, n);
   } else {
     return s;
@@ -144,7 +144,7 @@ function _deepEqual(actual, expected) {
   if (actual === expected) {
     return true;
 
-  } else if (Buffer.isBuffer(actual) && Buffer.isBuffer(expected)) {
+  } else if (IS_BUFFER(actual) && IS_BUFFER(expected)) {
     if (actual.length != expected.length) return false;
 
     for (var i = 0; i < actual.length; i++) {
@@ -155,13 +155,13 @@ function _deepEqual(actual, expected) {
 
   // 7.2. If the expected value is a Date object, the actual value is
   // equivalent if it is also a Date object that refers to the same time.
-  } else if (actual instanceof Date && expected instanceof Date) {
+  } else if (IS_DATE(actual) && IS_DATE(expected)) {
     return actual.getTime() === expected.getTime();
 
   // 7.3 If the expected value is a RegExp object, the actual value is
   // equivalent if it is also a RegExp object with the same source and
   // properties (`global`, `multiline`, `lastIndex`, `ignoreCase`).
-  } else if (actual instanceof RegExp && expected instanceof RegExp) {
+  } else if (IS_REGEXP(actual) && IS_REGEXP(expected)) {
     return actual.source === expected.source &&
            actual.global === expected.global &&
            actual.multiline === expected.multiline &&
@@ -170,7 +170,7 @@ function _deepEqual(actual, expected) {
 
   // 7.4. Other pairs that do not both pass typeof value == 'object',
   // equivalence is determined by ==.
-  } else if (typeof actual != 'object' && typeof expected != 'object') {
+  } else if (!IS_OBJECT(actual) && !IS_OBJECT(expected)) {
     return actual == expected;
 
   // 7.5 For all other Object pairs, including Array objects, equivalence is
@@ -184,16 +184,12 @@ function _deepEqual(actual, expected) {
   }
 }
 
-function isUndefinedOrNull(value) {
-  return value === null || value === undefined;
-}
-
 function isArguments(object) {
   return Object.prototype.toString.call(object) == '[object Arguments]';
 }
 
 function objEquiv(a, b) {
-  if (isUndefinedOrNull(a) || isUndefinedOrNull(b))
+  if (IS_NULL_OR_UNDEFINED(a) || IS_NULL_OR_UNDEFINED(b))
     return false;
   // an identical 'prototype' property.
   if (a.prototype !== b.prototype) return false;
@@ -281,7 +277,7 @@ function expectedException(actual, expected) {
 function _throws(shouldThrow, block, expected, message) {
   var actual;
 
-  if (typeof expected === 'string') {
+  if (IS_STRING(expected)) {
     message = expected;
     expected = null;
   }
diff --git a/lib/buffer.js b/lib/buffer.js
index deb946f..83f23e9 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -48,34 +48,24 @@ function createPool() {
 
 
 function Buffer(subject, encoding) {
-  if (!(this instanceof Buffer))
+  if (!IS_BUFFER(this))
     return new Buffer(subject, encoding);
 
-  var type = typeof subject;
-
-  switch (type) {
-    case 'number':
-      this.length = subject > 0 ? Math.floor(subject) : 0;
-      break;
-
-    case 'string':
-      this.length = Buffer.byteLength(subject, encoding = encoding || 'utf8');
-      break;
-
-    case 'object':
-      this.length = +subject.length > 0 ? Math.floor(+subject.length) : 0;
-      break;
-
+  if (IS_NUMBER(subject))
+    this.length = subject > 0 ? Math.floor(subject) : 0;
+  else if (IS_STRING(subject))
+    this.length = Buffer.byteLength(subject, encoding = encoding || 'utf8');
+  else if (IS_OBJECT(subject))
+    this.length = +subject.length > 0 ? Math.floor(+subject.length) : 0;
+  else if (IS_UNDEFINED(subject)) {
     // undef first arg returns unallocated buffer, also assumes length passed.
     // this is a stop-gap for now while look for better architecture.
     // for internal use only.
-    case 'undefined':
-      this.length = encoding;
-      return;
-
-    default:
-      throw new TypeError('must start with number, buffer, array or string');
+    this.length = encoding;
+    return;
   }
+  else
+    throw new TypeError('must start with number, buffer, array or string');
 
   if (this.length > kMaxLength)
     throw new RangeError('length > kMaxLength');
@@ -92,14 +82,14 @@ function Buffer(subject, encoding) {
     alloc(this, this.length);
   }
 
-  if (type !== 'number') {
-    if (type === 'string') {
+  if (!IS_NUMBER(subject)) {
+    if (IS_STRING(subject)) {
       // FIXME: the number of bytes hasn't changed, so why change the length?
       this.length = this.write(subject, 0, encoding);
     } else {
-      if (subject instanceof Buffer)
+      if (IS_BUFFER(subject))
         this.copy(subject, 0, 0, this.length);
-      else if (typeof subject.length === 'number' || Array.isArray(subject))
+      else if (IS_NUMBER(subject.length) || IS_ARRAY(subject))
         for (var i = 0; i < this.length; i++)
           this[i] = subject[i];
     }
@@ -118,7 +108,7 @@ function SlowBuffer(length) {
 // Static methods
 
 Buffer.isBuffer = function isBuffer(b) {
-  return b instanceof Buffer;
+  return IS_BUFFER(b);
 };
 
 
@@ -144,10 +134,10 @@ Buffer.isEncoding = function(encoding) {
 
 
 Buffer.concat = function(list, length) {
-  if (!Array.isArray(list))
+  if (!IS_ARRAY(list))
     throw new TypeError('Usage: Buffer.concat(list[, length])');
 
-  if (length === undefined) {
+  if (IS_UNDEFINED(length)) {
     length = 0;
     for (var i = 0; i < list.length; i++)
       length += list[i].length;
@@ -184,7 +174,7 @@ Buffer.prototype.toString = function(encoding, start, end) {
   encoding = !!encoding ? (encoding + '').toLowerCase() : 'utf8';
 
   start = ~~start;
-  end = (end === undefined) ? this.length : ~~end;
+  end = IS_UNDEFINED(end) ? this.length : ~~end;
 
   if (start < 0) start = 0;
   if (end > this.length) end = this.length;
@@ -253,7 +243,7 @@ var writeMsg = '.write(string, encoding, offset, length) is deprecated.' +
                ' Use write(string, offset, length, encoding) instead.';
 Buffer.prototype.write = function(string, offset, length, encoding) {
   // allow write(string, encoding)
-  if (typeof offset === 'string' && length === undefined) {
+  if (IS_STRING(offset) && IS_UNDEFINED(length)) {
     encoding = offset;
     offset = 0;
 
@@ -286,7 +276,7 @@ Buffer.prototype.write = function(string, offset, length, encoding) {
   }
 
   var remaining = this.length - offset;
-  if (length === undefined || length > remaining)
+  if (IS_UNDEFINED(length) || length > remaining)
     length = remaining;
 
   encoding = !!encoding ? (encoding + '').toLowerCase() : 'utf8';
@@ -346,7 +336,7 @@ Buffer.prototype.toJSON = function() {
 Buffer.prototype.slice = function(start, end) {
   var len = this.length;
   start = ~~start;
-  end = (end === undefined) ? len : ~~end;
+  end = IS_UNDEFINED(end) ? len : ~~end;
 
   if (start < 0) {
     start += len;
@@ -371,7 +361,7 @@ Buffer.prototype.slice = function(start, end) {
   sliceOnto(this, buf, start, end);
   buf.length = end - start;
   if (buf.length > 0)
-    buf.parent = this.parent === undefined ? this : this.parent;
+    buf.parent = IS_UNDEFINED(this.parent) ? this : this.parent;
 
   return buf;
 };
diff --git a/lib/child_process.js b/lib/child_process.js
index 1ca3d8c..cfb40f0 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -39,7 +39,7 @@ function handleWrapGetter(name, callback) {
 
   Object.defineProperty(handleWraps, name, {
     get: function() {
-      if (cons !== undefined) return cons;
+      if (!IS_UNDEFINED(cons)) return cons;
       return cons = callback();
     }
   });
@@ -312,9 +312,9 @@ function getSocketList(type, slave, key) {
 var INTERNAL_PREFIX = 'NODE_';
 function handleMessage(target, message, handle) {
   var eventName = 'message';
-  if (message !== null &&
-      typeof message === 'object' &&
-      typeof message.cmd === 'string' &&
+  if (!IS_NULL(message) &&
+      IS_OBJECT(message) &&
+      IS_STRING(message.cmd) &&
       message.cmd.length > INTERNAL_PREFIX.length &&
       message.cmd.slice(0, INTERNAL_PREFIX.length) === INTERNAL_PREFIX) {
     eventName = 'internalMessage';
@@ -370,7 +370,7 @@ function setupChannel(target, channel) {
   target.on('internalMessage', function(message, handle) {
     // Once acknowledged - continue sending handles.
     if (message.cmd === 'NODE_HANDLE_ACK') {
-      assert(Array.isArray(target._handleQueue));
+      assert(IS_ARRAY(target._handleQueue));
       var queue = target._handleQueue;
       target._handleQueue = null;
       queue.forEach(function(args) {
@@ -399,7 +399,7 @@ function setupChannel(target, channel) {
   });
 
   target.send = function(message, handle) {
-    if (typeof message === 'undefined') {
+    if (IS_UNDEFINED(message)) {
       throw new TypeError('message cannot be undefined');
     }
 
@@ -512,7 +512,7 @@ exports.fork = function(modulePath /*, args, options*/) {
 
   // Get options and args arguments.
   var options, args, execArgv;
-  if (Array.isArray(arguments[1])) {
+  if (IS_ARRAY(arguments[1])) {
     args = arguments[1];
     options = util._extend({}, arguments[2]);
   } else {
@@ -557,7 +557,7 @@ exports._forkChild = function(fd) {
 exports.exec = function(command /*, options, callback */) {
   var file, args, options, callback;
 
-  if (typeof arguments[1] === 'function') {
+  if (IS_FUNCTION(arguments[1])) {
     options = undefined;
     callback = arguments[1];
   } else {
@@ -593,11 +593,11 @@ exports.execFile = function(file /* args, options, callback */) {
 
   // Parse the parameters.
 
-  if (typeof arguments[arguments.length - 1] === 'function') {
+  if (IS_FUNCTION(arguments[arguments.length - 1])) {
     callback = arguments[arguments.length - 1];
   }
 
-  if (Array.isArray(arguments[1])) {
+  if (IS_ARRAY(arguments[1])) {
     args = arguments[1];
     options = util._extend(options, arguments[2]);
   } else {
@@ -835,14 +835,14 @@ ChildProcess.prototype.spawn = function(options) {
       stdio = options.stdio || 'pipe';
 
   // Replace shortcut with an array
-  if (typeof stdio === 'string') {
+  if (IS_STRING(stdio)) {
     switch (stdio) {
       case 'ignore': stdio = ['ignore', 'ignore', 'ignore']; break;
       case 'pipe': stdio = ['pipe', 'pipe', 'pipe']; break;
       case 'inherit': stdio = [0, 1, 2]; break;
       default: throw new TypeError('Incorrect value of stdio option: ' + stdio);
     }
-  } else if (!Array.isArray(stdio)) {
+  } else if (!IS_ARRAY(stdio)) {
     throw new TypeError('Incorrect value of stdio option: ' + stdio);
   }
 
@@ -864,16 +864,16 @@ ChildProcess.prototype.spawn = function(options) {
     }
 
     // Defaults
-    if (stdio === undefined || stdio === null) {
+    if (IS_NULL_OR_UNDEFINED(stdio)) {
       stdio = i < 3 ? 'pipe' : 'ignore';
     }
 
     if (stdio === 'ignore') {
       acc.push({type: 'ignore'});
-    } else if (stdio === 'pipe' || typeof stdio === 'number' && stdio < 0) {
+    } else if (stdio === 'pipe' || IS_NUMBER(stdio) && stdio < 0) {
       acc.push({type: 'pipe', handle: createPipe()});
     } else if (stdio === 'ipc') {
-      if (ipc !== undefined) {
+      if (!IS_UNDEFINED(ipc)) {
         // Cleanup previously created pipes
         cleanup();
         throw Error('Child process can have only one IPC pipe');
@@ -883,7 +883,7 @@ ChildProcess.prototype.spawn = function(options) {
       ipcFd = i;
 
       acc.push({ type: 'pipe', handle: ipc, ipc: true });
-    } else if (typeof stdio === 'number' || typeof stdio.fd === 'number') {
+    } else if (IS_NUMBER(stdio) || IS_NUMBER(stdio.fd)) {
       acc.push({ type: 'fd', fd: stdio.fd || stdio });
     } else if (getHandleWrapType(stdio) || getHandleWrapType(stdio.handle) ||
                getHandleWrapType(stdio._handle)) {
@@ -907,7 +907,7 @@ ChildProcess.prototype.spawn = function(options) {
 
   options.stdio = stdio;
 
-  if (ipc !== undefined) {
+  if (!IS_UNDEFINED(ipc)) {
     // Let child process know about opened IPC channel
     options.envPairs = options.envPairs || [];
     options.envPairs.push('NODE_CHANNEL_FD=' + ipcFd);
@@ -952,19 +952,19 @@ ChildProcess.prototype.spawn = function(options) {
     }
   });
 
-  this.stdin = stdio.length >= 1 && stdio[0].socket !== undefined ?
+  this.stdin = stdio.length >= 1 && !IS_UNDEFINED(stdio[0].socket) ?
       stdio[0].socket : null;
-  this.stdout = stdio.length >= 2 && stdio[1].socket !== undefined ?
+  this.stdout = stdio.length >= 2 && !IS_UNDEFINED(stdio[1].socket) ?
       stdio[1].socket : null;
-  this.stderr = stdio.length >= 3 && stdio[2].socket !== undefined ?
+  this.stderr = stdio.length >= 3 && !IS_UNDEFINED(stdio[2].socket) ?
       stdio[2].socket : null;
 
   this.stdio = stdio.map(function(stdio) {
-    return stdio.socket === undefined ? null : stdio.socket;
+    return IS_UNDEFINED(stdio.socket) ? null : stdio.socket;
   });
 
   // Add .send() method and start listening for IPC data
-  if (ipc !== undefined) setupChannel(this, ipc);
+  if (!IS_UNDEFINED(ipc)) setupChannel(this, ipc);
 
   return err;
 };
@@ -985,7 +985,7 @@ ChildProcess.prototype.kill = function(sig) {
     signal = constants[sig];
   }
 
-  if (signal === undefined) {
+  if (IS_UNDEFINED(signal)) {
     throw new Error('Unknown signal: ' + sig);
   }
 
diff --git a/lib/cluster.js b/lib/cluster.js
index b585934..6503892 100644
--- a/lib/cluster.js
+++ b/lib/cluster.js
@@ -68,7 +68,7 @@ function SharedHandle(key, address, port, addressType, backlog, fd) {
   else
     rval = net._createServerHandle(address, port, addressType, fd);
 
-  if (typeof rval === 'number')
+  if (IS_NUMBER(rval))
     this.errno = rval;
   else
     this.handle = rval;
@@ -135,7 +135,7 @@ RoundRobinHandle.prototype.add = function(worker, send) {
     self.handoff(worker);  // In case there are connections pending.
   }
 
-  if (this.server === null) return done();
+  if (IS_NULL(this.server)) return done();
   // Still busy binding.
   this.server.once('listening', done);
   this.server.once('error', function(err) {
@@ -166,7 +166,7 @@ RoundRobinHandle.prototype.handoff = function(worker) {
     return;  // Worker is closing (or has closed) the server.
   }
   var handle = this.handles.shift();
-  if (typeof handle === 'undefined') {
+  if (IS_UNDEFINED(handle)) {
     this.free.push(worker);  // Add to ready queue again.
     return;
   }
@@ -225,7 +225,7 @@ function masterInit() {
     'rr': SCHED_RR
   }[process.env.NODE_CLUSTER_SCHED_POLICY];
 
-  if (typeof schedulingPolicy === 'undefined') {
+  if (IS_UNDEFINED(schedulingPolicy)) {
     // FIXME Round-robin doesn't perform well on Windows right now due to the
     // way IOCP is wired up. Bert is going to fix that, eventually.
     schedulingPolicy = (process.platform === 'win32') ? SCHED_NONE : SCHED_RR;
@@ -367,7 +367,7 @@ function masterInit() {
                 message.fd];
     var key = args.join(':');
     var handle = handles[key];
-    if (typeof handle === 'undefined') {
+    if (IS_UNDEFINED(handle)) {
       var constructor = RoundRobinHandle;
       // UDP is exempt from round-robin connection balancing for what should
       // be obvious reasons: it's connectionless. There is nothing to send to
@@ -474,7 +474,7 @@ function workerInit() {
       delete handles[key];
       return close.apply(this, arguments);
     };
-    assert(typeof handles[key] === 'undefined');
+    assert(IS_UNDEFINED(handles[key]));
     handles[key] = handle;
     cb(handle);
   }
@@ -511,7 +511,7 @@ function workerInit() {
         // the ack by the master process in which we can still receive handles.
         // onconnection() below handles that by sending those handles back to
         // the master.
-        if (typeof key === 'undefined') return;
+        if (IS_UNDEFINED(key)) return;
         send({ act: 'close', key: key });
         delete handles[key];
         key = undefined;
@@ -529,7 +529,7 @@ function workerInit() {
       if (message.sockname) {
         handle.getsockname = getsockname;  // TCP handles only.
       }
-      assert(typeof handles[key] === 'undefined');
+      assert(IS_UNDEFINED(handles[key]));
       handles[key] = handle;
       cb(handle);
     }
@@ -539,7 +539,7 @@ function workerInit() {
   function onconnection(message, handle) {
     var key = message.key;
     var server = handles[key];
-    var accepted = (typeof server !== 'undefined');
+    var accepted = !IS_UNDEFINED(server);
     send({ ack: message.seq, accepted: accepted });
     if (accepted) server.onconnection(0, handle);
   }
@@ -585,7 +585,7 @@ function internal(worker, cb) {
   return function(message, handle) {
     if (message.cmd !== 'NODE_CLUSTER') return;
     var fn = cb;
-    if (typeof message.ack !== 'undefined') {
+    if (!IS_UNDEFINED(message.ack)) {
       fn = callbacks[message.ack];
       delete callbacks[message.ack];
     }
diff --git a/lib/console.js b/lib/console.js
index 66578b6..fd7722f 100644
--- a/lib/console.js
+++ b/lib/console.js
@@ -25,7 +25,7 @@ function Console(stdout, stderr) {
   if (!(this instanceof Console)) {
     return new Console(stdout, stderr);
   }
-  if (!stdout || typeof stdout.write !== 'function') {
+  if (!stdout || !IS_FUNCTION(stdout.write)) {
     throw new TypeError('Console expects a writable stream instance');
   }
   if (!stderr) {
diff --git a/lib/crypto.js b/lib/crypto.js
index 90e139a..c450f1c 100644
--- a/lib/crypto.js
+++ b/lib/crypto.js
@@ -43,7 +43,7 @@ var util = require('util');
 // to break them unnecessarily.
 function toBuf(str, encoding) {
   encoding = encoding || 'binary';
-  if (typeof str === 'string') {
+  if (IS_STRING(str)) {
     if (encoding === 'buffer')
       encoding = 'binary';
     str = new Buffer(str, encoding);
@@ -100,7 +100,7 @@ exports.createCredentials = function(options, context) {
   if (options.ciphers) c.context.setCiphers(options.ciphers);
 
   if (options.ca) {
-    if (Array.isArray(options.ca)) {
+    if (IS_ARRAY(options.ca)) {
       for (var i = 0, len = options.ca.length; i < len; i++) {
         c.context.addCACert(options.ca[i]);
       }
@@ -112,7 +112,7 @@ exports.createCredentials = function(options, context) {
   }
 
   if (options.crl) {
-    if (Array.isArray(options.crl)) {
+    if (IS_ARRAY(options.crl)) {
       for (var i = 0, len = options.crl.length; i < len; i++) {
         c.context.addCRL(options.crl[i]);
       }
@@ -198,7 +198,7 @@ Hash.prototype._flush = function(callback) {
 
 Hash.prototype.update = function(data, encoding) {
   encoding = encoding || exports.DEFAULT_ENCODING;
-  if (encoding === 'buffer' && typeof data === 'string')
+  if (encoding === 'buffer' && IS_STRING(data))
     encoding = 'binary';
   this._binding.update(data, encoding);
   return this;
@@ -539,7 +539,7 @@ DiffieHellman.prototype.setPrivateKey = function(key, encoding) {
 
 
 exports.pbkdf2 = function(password, salt, iterations, keylen, callback) {
-  if (typeof callback !== 'function')
+  if (!IS_FUNCTION(callback))
     throw new Error('No callback provided to pbkdf2');
 
   return pbkdf2(password, salt, iterations, keylen, callback);
diff --git a/lib/dgram.js b/lib/dgram.js
index 7f27998..1ac5c27 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -91,7 +91,7 @@ function newHandle(type) {
 
 exports._createSocketHandle = function(address, port, addressType, fd) {
   // Opening an existing fd is not supported for UDP handles.
-  assert(typeof fd !== 'number' || fd < 0);
+  assert(!IS_NUMBER(fd) || fd < 0);
 
   var handle = newHandle(addressType);
 
@@ -119,7 +119,7 @@ function Socket(type, listener) {
   this.type = type;
   this.fd = null; // compatibility hack
 
-  if (typeof listener === 'function')
+  if (IS_FUNCTION(listener))
     this.on('message', listener);
 }
 util.inherits(Socket, events.EventEmitter);
@@ -165,7 +165,7 @@ Socket.prototype.bind = function(/*port, address, callback*/) {
 
   this._bindState = BIND_STATE_BINDING;
 
-  if (typeof arguments[arguments.length - 1] === 'function')
+  if (IS_FUNCTION(arguments[arguments.length - 1]))
     self.once('listening', arguments[arguments.length - 1]);
 
   var UDP = process.binding('udp_wrap').UDP;
@@ -177,7 +177,7 @@ Socket.prototype.bind = function(/*port, address, callback*/) {
 
   var port = arguments[0];
   var address = arguments[1];
-  if (typeof address === 'function') address = '';  // a.k.a. "any address"
+  if (IS_FUNCTION(address)) address = '';  // a.k.a. "any address"
 
   // resolve address first
   self._handle.lookup(address, function(err, ip) {
@@ -225,10 +225,10 @@ Socket.prototype.sendto = function(buffer,
                                    port,
                                    address,
                                    callback) {
-  if (typeof offset !== 'number' || typeof length !== 'number')
+  if (!IS_NUMBER(offset) || !IS_NUMBER(length))
     throw new Error('send takes offset and length as args 2 and 3');
 
-  if (typeof address !== 'string')
+  if (!IS_STRING(address))
     throw new Error(this.type + ' sockets must send to port, address');
 
   this.send(buffer, offset, length, port, address, callback);
@@ -243,7 +243,7 @@ Socket.prototype.send = function(buffer,
                                  callback) {
   var self = this;
 
-  if (!Buffer.isBuffer(buffer))
+  if (!IS_BUFFER(buffer))
     throw new TypeError('First argument must be a buffer object.');
 
   if (offset >= buffer.length)
@@ -335,7 +335,7 @@ Socket.prototype.setBroadcast = function(arg) {
 
 
 Socket.prototype.setTTL = function(arg) {
-  if (typeof arg !== 'number') {
+  if (!IS_NUMBER(arg)) {
     throw new TypeError('Argument must be a number');
   }
 
@@ -349,7 +349,7 @@ Socket.prototype.setTTL = function(arg) {
 
 
 Socket.prototype.setMulticastTTL = function(arg) {
-  if (typeof arg !== 'number') {
+  if (!IS_NUMBER(arg)) {
     throw new TypeError('Argument must be a number');
   }
 
diff --git a/lib/dns.js b/lib/dns.js
index 23bd758..e92b180 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -61,7 +61,7 @@ function errnoException(err, syscall) {
 //   callback.immediately = true;
 // }
 function makeAsync(callback) {
-  if (typeof callback !== 'function') {
+  if (!IS_FUNCTION(callback)) {
     return callback;
   }
   return function asyncCallback() {
@@ -178,7 +178,7 @@ exports.reverse = resolveMap.PTR = resolver('getHostByAddr');
 
 exports.resolve = function(domain, type_, callback_) {
   var resolver, callback;
-  if (typeof type_ == 'string') {
+  if (IS_STRING(type_)) {
     resolver = resolveMap[type_];
     callback = callback_;
   } else {
@@ -186,7 +186,7 @@ exports.resolve = function(domain, type_, callback_) {
     callback = type_;
   }
 
-  if (typeof resolver === 'function') {
+  if (IS_FUNCTION(resolver)) {
     return resolver(domain, callback);
   } else {
     throw new Error('Unknown type "' + type_ + '"');
diff --git a/lib/domain.js b/lib/domain.js
index 148d3a2..364d8c7 100644
--- a/lib/domain.js
+++ b/lib/domain.js
@@ -219,7 +219,7 @@ Domain.prototype.dispose = function() {
     // so it's quite possible that calling some of these methods
     // might cause additional exceptions to be thrown.
     endMethods.forEach(function(method) {
-      if (typeof m[method] === 'function') {
+      if (IS_FUNCTION(m[method])) {
         try {
           m[method]();
         } catch (er) {}
diff --git a/lib/events.js b/lib/events.js
index 9c2ba54..b69dc8f 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -49,7 +49,7 @@ EventEmitter.defaultMaxListeners = 10;
 // Obviously not all Emitters should be limited to 10. This function allows
 // that to be increased. Set to zero for unlimited.
 EventEmitter.prototype.setMaxListeners = function(n) {
-  if (typeof n !== 'number' || n < 0)
+  if (!IS_NUMBER(n) || n < 0)
     throw TypeError('n must be a positive number');
   this._maxListeners = n;
   return this;
@@ -64,8 +64,7 @@ EventEmitter.prototype.emit = function(type) {
   // If there is no 'error' event listener then throw.
   if (type === 'error') {
     if (!this._events.error ||
-        (typeof this._events.error === 'object' &&
-         !this._events.error.length)) {
+        (IS_OBJECT(this._events.error) && !this._events.error.length)) {
       er = arguments[1];
       if (this.domain) {
         if (!er) er = new TypeError('Uncaught, unspecified "error" event.');
@@ -84,13 +83,13 @@ EventEmitter.prototype.emit = function(type) {
 
   handler = this._events[type];
 
-  if (typeof handler === 'undefined')
+  if (IS_UNDEFINED(handler))
     return false;
 
   if (this.domain && this !== process)
     this.domain.enter();
 
-  if (typeof handler === 'function') {
+  if (IS_FUNCTION(handler)) {
     switch (arguments.length) {
       // fast cases
       case 1:
@@ -110,7 +109,7 @@ EventEmitter.prototype.emit = function(type) {
           args[i - 1] = arguments[i];
         handler.apply(this, args);
     }
-  } else if (typeof handler === 'object') {
+  } else if (IS_OBJECT(handler)) {
     len = arguments.length;
     args = new Array(len - 1);
     for (i = 1; i < len; i++)
@@ -131,7 +130,7 @@ EventEmitter.prototype.emit = function(type) {
 EventEmitter.prototype.addListener = function(type, listener) {
   var m;
 
-  if (typeof listener !== 'function')
+  if (!IS_FUNCTION(listener))
     throw TypeError('listener must be a function');
 
   if (!this._events)
@@ -140,13 +139,13 @@ EventEmitter.prototype.addListener = function(type, listener) {
   // To avoid recursion in the case that type === "newListener"! Before
   // adding it to the listeners, first emit "newListener".
   if (this._events.newListener)
-    this.emit('newListener', type, typeof listener.listener === 'function' ?
-              listener.listener : listener);
+    this.emit('newListener', type,
+              IS_FUNCTION(listener.listener) ? listener.listener : listener);
 
   if (!this._events[type])
     // Optimize the case of one listener. Don't need the extra array object.
     this._events[type] = listener;
-  else if (typeof this._events[type] === 'object')
+  else if (IS_OBJECT(this._events[type]))
     // If we've already got an array, just append.
     this._events[type].push(listener);
   else
@@ -154,9 +153,9 @@ EventEmitter.prototype.addListener = function(type, listener) {
     this._events[type] = [this._events[type], listener];
 
   // Check for listener leak
-  if (typeof this._events[type] === 'object' && !this._events[type].warned) {
+  if (IS_OBJECT(this._events[type]) && !this._events[type].warned) {
     var m;
-    if (this._maxListeners !== undefined) {
+    if (!IS_UNDEFINED(this._maxListeners)) {
       m = this._maxListeners;
     } else {
       m = EventEmitter.defaultMaxListeners;
@@ -178,7 +177,7 @@ EventEmitter.prototype.addListener = function(type, listener) {
 EventEmitter.prototype.on = EventEmitter.prototype.addListener;
 
 EventEmitter.prototype.once = function(type, listener) {
-  if (typeof listener !== 'function')
+  if (!IS_FUNCTION(listener))
     throw TypeError('listener must be a function');
 
   function g() {
@@ -196,7 +195,7 @@ EventEmitter.prototype.once = function(type, listener) {
 EventEmitter.prototype.removeListener = function(type, listener) {
   var list, position, length, i;
 
-  if (typeof listener !== 'function')
+  if (!IS_FUNCTION(listener))
     throw TypeError('listener must be a function');
 
   if (!this._events || !this._events[type])
@@ -207,12 +206,12 @@ EventEmitter.prototype.removeListener = function(type, listener) {
   position = -1;
 
   if (list === listener ||
-      (typeof list.listener === 'function' && list.listener === listener)) {
+      (IS_FUNCTION(list.listener) && list.listener === listener)) {
     this._events[type] = undefined;
     if (this._events.removeListener)
       this.emit('removeListener', type, listener);
 
-  } else if (typeof list === 'object') {
+  } else if (IS_OBJECT(list)) {
     for (i = length; i-- > 0;) {
       if (list[i] === listener ||
           (list[i].listener && list[i].listener === listener)) {
@@ -266,7 +265,7 @@ EventEmitter.prototype.removeAllListeners = function(type) {
 
   listeners = this._events[type];
 
-  if (typeof listeners === 'function') {
+  if (IS_FUNCTION(listeners)) {
     this.removeListener(type, listeners);
   } else {
     // LIFO order
@@ -282,7 +281,7 @@ EventEmitter.prototype.listeners = function(type) {
   var ret;
   if (!this._events || !this._events[type])
     ret = [];
-  else if (typeof this._events[type] === 'function')
+  else if (IS_FUNCTION(this._events[type]))
     ret = [this._events[type]];
   else
     ret = this._events[type].slice();
@@ -293,7 +292,7 @@ EventEmitter.listenerCount = function(emitter, type) {
   var ret;
   if (!emitter._events || !emitter._events[type])
     ret = 0;
-  else if (typeof emitter._events[type] === 'function')
+  else if (IS_FUNCTION(emitter._events[type]))
     ret = 1;
   else
     ret = emitter._events[type].length;
diff --git a/lib/fs.js b/lib/fs.js
index 39d31ca..b1ca7aa 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -81,14 +81,14 @@ function rethrow() {
 }
 
 function maybeCallback(cb) {
-  return typeof cb === 'function' ? cb : rethrow();
+  return IS_FUNCTION(cb) ? cb : rethrow();
 }
 
 // Ensure that callbacks run in the global context. Only use this function
 // for callbacks that are passed to the binding layer, callbacks that are
 // invoked from JS already run in the proper scope.
 function makeCallback(cb) {
-  if (typeof cb !== 'function') {
+  if (!IS_FUNCTION(cb)) {
     return rethrow();
   }
 
@@ -171,13 +171,13 @@ fs.existsSync = function(path) {
 fs.readFile = function(path, options, callback_) {
   var callback = maybeCallback(arguments[arguments.length - 1]);
 
-  if (typeof options === 'function' || !options) {
+  if (IS_FUNCTION(options) || !options) {
     options = { encoding: null, flag: 'r' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, flag: 'r' };
   } else if (!options) {
     options = { encoding: null, flag: 'r' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
 
@@ -260,9 +260,9 @@ fs.readFile = function(path, options, callback_) {
 fs.readFileSync = function(path, options) {
   if (!options) {
     options = { encoding: null, flag: 'r' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, flag: 'r' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
 
@@ -332,7 +332,7 @@ fs.readFileSync = function(path, options) {
 // Used by binding.open and friends
 function stringToFlags(flag) {
   // Only mess with strings
-  if (typeof flag !== 'string') {
+  if (!IS_STRING(flag)) {
     return flag;
   }
 
@@ -381,16 +381,13 @@ fs.closeSync = function(fd) {
 };
 
 function modeNum(m, def) {
-  switch (typeof m) {
-    case 'number': return m;
-    case 'string': return parseInt(m, 8);
-    default:
-      if (def) {
-        return modeNum(def);
-      } else {
-        return undefined;
-      }
-  }
+  if (IS_NUMBER(m))
+    return m;
+  if (IS_STRING(m))
+    return parseInt(m, 8);
+  if (def)
+    return modeNum(def);
+  return undefined;
 }
 
 fs.open = function(path, flags, mode, callback) {
@@ -411,7 +408,7 @@ fs.openSync = function(path, flags, mode) {
 };
 
 fs.read = function(fd, buffer, offset, length, position, callback) {
-  if (!Buffer.isBuffer(buffer)) {
+  if (!IS_BUFFER(buffer)) {
     // legacy string interface (fd, length, position, encoding, callback)
     var cb = arguments[4],
         encoding = arguments[3];
@@ -442,7 +439,7 @@ fs.read = function(fd, buffer, offset, length, position, callback) {
 
 fs.readSync = function(fd, buffer, offset, length, position) {
   var legacy = false;
-  if (!Buffer.isBuffer(buffer)) {
+  if (!IS_BUFFER(buffer)) {
     // legacy string interface (fd, length, position, encoding, callback)
     legacy = true;
     var encoding = arguments[3];
@@ -466,7 +463,7 @@ fs.readSync = function(fd, buffer, offset, length, position) {
 };
 
 fs.write = function(fd, buffer, offset, length, position, callback) {
-  if (!Buffer.isBuffer(buffer)) {
+  if (!IS_BUFFER(buffer)) {
     // legacy string interface (fd, data, position, encoding, callback)
     callback = arguments[4];
     position = arguments[2];
@@ -478,7 +475,7 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
   }
 
   if (!length) {
-    if (typeof callback == 'function') {
+    if (IS_FUNCTION(callback)) {
       process.nextTick(function() {
         callback(undefined, 0);
       });
@@ -497,7 +494,7 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
 };
 
 fs.writeSync = function(fd, buffer, offset, length, position) {
-  if (!Buffer.isBuffer(buffer)) {
+  if (!IS_BUFFER(buffer)) {
     // legacy string interface (fd, data, position, encoding)
     position = arguments[2];
     assertEncoding(arguments[3]);
@@ -528,14 +525,14 @@ fs.renameSync = function(oldPath, newPath) {
 };
 
 fs.truncate = function(path, len, callback) {
-  if (typeof path === 'number') {
+  if (IS_NUMBER(path)) {
     // legacy
     return fs.ftruncate(path, len, callback);
   }
-  if (typeof len === 'function') {
+  if (IS_FUNCTION(len)) {
     callback = len;
     len = 0;
-  } else if (typeof len === 'undefined') {
+  } else if (IS_UNDEFINED(len)) {
     len = 0;
   }
   callback = maybeCallback(callback);
@@ -550,11 +547,11 @@ fs.truncate = function(path, len, callback) {
 };
 
 fs.truncateSync = function(path, len) {
-  if (typeof path === 'number') {
+  if (IS_NUMBER(path)) {
     // legacy
     return fs.ftruncateSync(path, len);
   }
-  if (typeof len === 'undefined') {
+  if (IS_UNDEFINED(len)) {
     len = 0;
   }
   // allow error to be thrown, but still close fd.
@@ -568,17 +565,17 @@ fs.truncateSync = function(path, len) {
 };
 
 fs.ftruncate = function(fd, len, callback) {
-  if (typeof len === 'function') {
+  if (IS_FUNCTION(len)) {
     callback = len;
     len = 0;
-  } else if (typeof len === 'undefined') {
+  } else if (IS_UNDEFINED(len)) {
     len = 0;
   }
   binding.ftruncate(fd, len, makeCallback(callback));
 };
 
 fs.ftruncateSync = function(fd, len) {
-  if (typeof len === 'undefined') {
+  if (IS_UNDEFINED(len)) {
     len = 0;
   }
   return binding.ftruncate(fd, len);
@@ -612,7 +609,7 @@ fs.fsyncSync = function(fd) {
 };
 
 fs.mkdir = function(path, mode, callback) {
-  if (typeof mode === 'function') callback = mode;
+  if (IS_FUNCTION(mode)) callback = mode;
   callback = makeCallback(callback);
   if (!nullCheck(path, callback)) return;
   binding.mkdir(pathModule._makeLong(path),
@@ -692,7 +689,7 @@ function preprocessSymlinkDestination(path, type) {
 }
 
 fs.symlink = function(destination, path, type_, callback) {
-  var type = (typeof type_ === 'string' ? type_ : null);
+  var type = (IS_STRING(type_) ? type_ : null);
   var callback = makeCallback(arguments[arguments.length - 1]);
 
   if (!nullCheck(destination, callback)) return;
@@ -705,7 +702,7 @@ fs.symlink = function(destination, path, type_, callback) {
 };
 
 fs.symlinkSync = function(destination, path, type) {
-  type = (typeof type === 'string' ? type : null);
+  type = (IS_STRING(type) ? type : null);
 
   nullCheck(destination);
   nullCheck(path);
@@ -843,10 +840,10 @@ fs.chownSync = function(path, uid, gid) {
 
 // converts Date or number to a fractional UNIX timestamp
 function toUnixTimestamp(time) {
-  if (typeof time == 'number') {
+  if (IS_NUMBER(time)) {
     return time;
   }
-  if (time instanceof Date) {
+  if (IS_DATE(time)) {
     // convert to 123.456 UNIX timestamp
     return time.getTime() / 1000;
   }
@@ -909,13 +906,13 @@ function writeAll(fd, buffer, offset, length, position, callback) {
 fs.writeFile = function(path, data, options, callback) {
   var callback = maybeCallback(arguments[arguments.length - 1]);
 
-  if (typeof options === 'function' || !options) {
+  if (IS_FUNCTION(options) || !options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'w' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, mode: 438, flag: 'w' };
   } else if (!options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'w' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
 
@@ -926,7 +923,7 @@ fs.writeFile = function(path, data, options, callback) {
     if (openErr) {
       if (callback) callback(openErr);
     } else {
-      var buffer = Buffer.isBuffer(data) ? data : new Buffer('' + data,
+      var buffer = IS_BUFFER(data) ? data : new Buffer('' + data,
           options.encoding || 'utf8');
       var position = /a/.test(flag) ? null : 0;
       writeAll(fd, buffer, 0, buffer.length, position, callback);
@@ -937,9 +934,9 @@ fs.writeFile = function(path, data, options, callback) {
 fs.writeFileSync = function(path, data, options) {
   if (!options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'w' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, mode: 438, flag: 'w' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
 
@@ -947,7 +944,7 @@ fs.writeFileSync = function(path, data, options) {
 
   var flag = options.flag || 'w';
   var fd = fs.openSync(path, flag, options.mode);
-  if (!Buffer.isBuffer(data)) {
+  if (!IS_BUFFER(data)) {
     data = new Buffer('' + data, options.encoding || 'utf8');
   }
   var written = 0;
@@ -966,13 +963,13 @@ fs.writeFileSync = function(path, data, options) {
 fs.appendFile = function(path, data, options, callback_) {
   var callback = maybeCallback(arguments[arguments.length - 1]);
 
-  if (typeof options === 'function' || !options) {
+  if (IS_FUNCTION(options) || !options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'a' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, mode: 438, flag: 'a' };
   } else if (!options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'a' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
 
@@ -984,9 +981,9 @@ fs.appendFile = function(path, data, options, callback_) {
 fs.appendFileSync = function(path, data, options) {
   if (!options) {
     options = { encoding: 'utf8', mode: 438 /*=0666*/, flag: 'a' };
-  } else if (typeof options === 'string') {
+  } else if (IS_STRING(options)) {
     options = { encoding: options, mode: 438, flag: 'a' };
-  } else if (typeof options !== 'object') {
+  } else if (!IS_OBJECT(options)) {
     throw new TypeError('Bad arguments');
   }
   if (!options.flag)
@@ -1033,7 +1030,7 @@ fs.watch = function(filename) {
   var options;
   var listener;
 
-  if ('object' == typeof arguments[1]) {
+  if (IS_OBJECT(arguments[1])) {
     options = arguments[1];
     listener = arguments[2];
   } else {
@@ -1041,7 +1038,7 @@ fs.watch = function(filename) {
     listener = arguments[1];
   }
 
-  if (options.persistent === undefined) options.persistent = true;
+  if (IS_UNDEFINED(options.persistent)) options.persistent = true;
 
   watcher = new FSWatcher();
   watcher.start(filename, options.persistent);
@@ -1113,7 +1110,7 @@ fs.watchFile = function(filename) {
     persistent: true
   };
 
-  if ('object' == typeof arguments[1]) {
+  if (IS_OBJECT(arguments[1])) {
     options = util._extend(options, arguments[1]);
     listener = arguments[2];
   } else {
@@ -1140,7 +1137,7 @@ fs.unwatchFile = function(filename, listener) {
 
   var stat = statWatchers[filename];
 
-  if (typeof listener === 'function') {
+  if (IS_FUNCTION(listener)) {
     stat.removeListener('change', listener);
   } else {
     stat.removeAllListeners('change');
@@ -1249,7 +1246,7 @@ fs.realpathSync = function realpathSync(p, cache) {
           linkTarget = seenLinks[id];
         }
       }
-      if (linkTarget === null) {
+      if (IS_NULL(linkTarget)) {
         fs.statSync(base);
         linkTarget = fs.readlinkSync(base);
       }
@@ -1271,7 +1268,7 @@ fs.realpathSync = function realpathSync(p, cache) {
 
 
 fs.realpath = function realpath(p, cache, cb) {
-  if (typeof cb !== 'function') {
+  if (!IS_FUNCTION(cb)) {
     cb = maybeCallback(cache);
     cache = null;
   }
@@ -1432,13 +1429,13 @@ function ReadStream(path, options) {
       options.autoClose : true;
   this.pos = undefined;
 
-  if (this.start !== undefined) {
-    if ('number' !== typeof this.start) {
+  if (!IS_UNDEFINED(this.start)) {
+    if (!IS_NUMBER(this.start)) {
       throw TypeError('start must be a Number');
     }
-    if (this.end === undefined) {
+    if (IS_UNDEFINED(this.end)) {
       this.end = Infinity;
-    } else if ('number' !== typeof this.end) {
+    } else if (!IS_NUMBER(this.end)) {
       throw TypeError('end must be a Number');
     }
 
@@ -1449,7 +1446,7 @@ function ReadStream(path, options) {
     this.pos = this.start;
   }
 
-  if (typeof this.fd !== 'number')
+  if (!IS_NUMBER(this.fd))
     this.open();
 
   this.on('end', function() {
@@ -1480,7 +1477,7 @@ ReadStream.prototype.open = function() {
 };
 
 ReadStream.prototype._read = function(n) {
-  if (typeof this.fd !== 'number')
+  if (!IS_NUMBER(this.fd))
     return this.once('open', function() {
       this._read(n);
     });
@@ -1501,7 +1498,7 @@ ReadStream.prototype._read = function(n) {
   var toRead = Math.min(pool.length - pool.used, n);
   var start = pool.used;
 
-  if (this.pos !== undefined)
+  if (!IS_UNDEFINED(this.pos))
     toRead = Math.min(this.end - this.pos + 1, toRead);
 
   // already read everything we were supposed to read!
@@ -1514,7 +1511,7 @@ ReadStream.prototype._read = function(n) {
   fs.read(this.fd, pool, pool.used, toRead, this.pos, onread);
 
   // move the pool positions, and internal position for reading.
-  if (this.pos !== undefined)
+  if (!IS_UNDEFINED(this.pos))
     this.pos += toRead;
   pool.used += toRead;
 
@@ -1540,7 +1537,7 @@ ReadStream.prototype.destroy = function() {
     return;
   this.destroyed = true;
 
-  if ('number' === typeof this.fd)
+  if (IS_NUMBER(this.fd))
     this.close();
 };
 
@@ -1549,8 +1546,8 @@ ReadStream.prototype.close = function(cb) {
   var self = this;
   if (cb)
     this.once('close', cb);
-  if (this.closed || 'number' !== typeof this.fd) {
-    if ('number' !== typeof this.fd) {
+  if (this.closed || !IS_NUMBER(this.fd)) {
+    if (!IS_NUMBER(this.fd)) {
       this.once('open', close);
       return;
     }
@@ -1598,8 +1595,8 @@ function WriteStream(path, options) {
   this.pos = undefined;
   this.bytesWritten = 0;
 
-  if (this.start !== undefined) {
-    if ('number' !== typeof this.start) {
+  if (!IS_UNDEFINED(this.start)) {
+    if (!IS_NUMBER(this.start)) {
       throw TypeError('start must be a Number');
     }
     if (this.start < 0) {
@@ -1609,7 +1606,7 @@ function WriteStream(path, options) {
     this.pos = this.start;
   }
 
-  if ('number' !== typeof this.fd)
+  if (!IS_NUMBER(this.fd))
     this.open();
 
   // dispose on finish.
@@ -1634,10 +1631,10 @@ WriteStream.prototype.open = function() {
 
 
 WriteStream.prototype._write = function(data, encoding, cb) {
-  if (!Buffer.isBuffer(data))
+  if (!IS_BUFFER(data))
     return this.emit('error', new Error('Invalid data'));
 
-  if (typeof this.fd !== 'number')
+  if (!IS_NUMBER(this.fd))
     return this.once('open', function() {
       this._write(data, encoding, cb);
     });
@@ -1652,7 +1649,7 @@ WriteStream.prototype._write = function(data, encoding, cb) {
     cb();
   });
 
-  if (this.pos !== undefined)
+  if (!IS_UNDEFINED(this.pos))
     this.pos += data.length;
 };
 
@@ -1686,10 +1683,10 @@ SyncWriteStream.prototype.write = function(data, arg1, arg2) {
 
   // parse arguments
   if (arg1) {
-    if (typeof arg1 === 'string') {
+    if (IS_STRING(arg1)) {
       encoding = arg1;
       cb = arg2;
-    } else if (typeof arg1 === 'function') {
+    } else if (IS_FUNCTION(arg1)) {
       cb = arg1;
     } else {
       throw new Error('bad arg');
@@ -1698,7 +1695,7 @@ SyncWriteStream.prototype.write = function(data, arg1, arg2) {
   assertEncoding(encoding);
 
   // Change strings to buffers. SLOW
-  if (typeof data == 'string') {
+  if (IS_STRING(data)) {
     data = new Buffer(data, encoding);
   }
 
diff --git a/lib/https.js b/lib/https.js
index afbdef1..4ffc1e6 100644
--- a/lib/https.js
+++ b/lib/https.js
@@ -60,21 +60,21 @@ exports.createServer = function(opts, requestListener) {
 // HTTPS agents.
 
 function createConnection(port, host, options) {
-  if (typeof port === 'object') {
+  if (IS_OBJECT(port)) {
     options = port;
-  } else if (typeof host === 'object') {
+  } else if (IS_OBJECT(host)) {
     options = host;
-  } else if (typeof options === 'object') {
+  } else if (IS_OBJECT(options)) {
     options = options;
   } else {
     options = {};
   }
 
-  if (typeof port === 'number') {
+  if (IS_NUMBER(port)) {
     options.port = port;
   }
 
-  if (typeof host === 'string') {
+  if (IS_STRING(host)) {
     options.host = host;
   }
 
@@ -115,7 +115,7 @@ Agent.prototype.getName = function(options) {
     name += options.pfx;
 
   name += ':';
-  if (options.rejectUnauthorized !== undefined)
+  if (!IS_UNDEFINED(options.rejectUnauthorized))
     name += options.rejectUnauthorized;
 
   return name;
diff --git a/lib/module.js b/lib/module.js
index d34ce10..ec0e761 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -352,7 +352,7 @@ Module.prototype.load = function(filename) {
 
 
 Module.prototype.require = function(path) {
-  assert(typeof path === 'string', 'path must be a string');
+  assert(IS_STRING(path), 'path must be a string');
   assert(path, 'missing path');
   return Module._load(path, this);
 };
diff --git a/lib/net.js b/lib/net.js
index 0b250ae..ddce74b 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -57,7 +57,7 @@ function createHandle(fd) {
 var debug = util.debuglog('net');
 
 function isPipeName(s) {
-  return typeof s === 'string' && toNumber(s) === false;
+  return IS_STRING(s) && toNumber(s) === false;
 }
 
 
@@ -90,7 +90,7 @@ exports.connect = exports.createConnection = function() {
 function normalizeConnectArgs(args) {
   var options = {};
 
-  if (typeof args[0] === 'object') {
+  if (IS_OBJECT(args[0])) {
     // connect(options, [cb])
     options = args[0];
   } else if (isPipeName(args[0])) {
@@ -99,13 +99,13 @@ function normalizeConnectArgs(args) {
   } else {
     // connect(port, [host], [cb])
     options.port = args[0];
-    if (typeof args[1] === 'string') {
+    if (IS_STRING(args[1])) {
       options.host = args[1];
     }
   }
 
   var cb = args[args.length - 1];
-  return (typeof cb === 'function') ? [options, cb] : [options];
+  return IS_FUNCTION(cb) ? [options, cb] : [options];
 }
 exports._normalizeConnectArgs = normalizeConnectArgs;
 
@@ -135,20 +135,16 @@ function Socket(options) {
   this._hadError = false;
   this._handle = null;
 
-  switch (typeof options) {
-    case 'number':
-      options = { fd: options }; // Legacy interface.
-      break;
-    case 'undefined':
-      options = {};
-      break;
-  }
+  if (IS_NUMBER(options))
+    options = { fd: options }; // Legacy interface.
+  else if (IS_UNDEFINED(options))
+    options = {};
 
   stream.Duplex.call(this, options);
 
   if (options.handle) {
     this._handle = options.handle; // private
-  } else if (typeof options.fd !== 'undefined') {
+  } else if (!IS_UNDEFINED(options.fd)) {
     this._handle = createHandle(options.fd);
     this._handle.open(options.fd);
     this.readable = options.readable !== false;
@@ -263,7 +259,7 @@ function onSocketEnd() {
 // of the other side sending a FIN.  The standard 'write after end'
 // is overly vague, and makes it seem like the user's code is to blame.
 function writeAfterFIN(chunk, encoding, cb) {
-  if (typeof encoding === 'function') {
+  if (IS_FUNCTION(encoding)) {
     cb = encoding;
     encoding = null;
   }
@@ -273,7 +269,7 @@ function writeAfterFIN(chunk, encoding, cb) {
   var self = this;
   // TODO: defer error events consistently everywhere, not just the cb
   self.emit('error', er);
-  if (typeof cb === 'function') {
+  if (IS_FUNCTION(cb)) {
     process.nextTick(function() {
       cb(er);
     });
@@ -326,7 +322,7 @@ Socket.prototype._onTimeout = function() {
 Socket.prototype.setNoDelay = function(enable) {
   // backwards compatibility: assume true when `enable` is omitted
   if (this._handle && this._handle.setNoDelay)
-    this._handle.setNoDelay(typeof enable === 'undefined' ? true : !!enable);
+    this._handle.setNoDelay(IS_UNDEFINED(enable) ? true : !!enable);
 };
 
 
@@ -605,7 +601,7 @@ Socket.prototype.__defineGetter__('localPort', function() {
 
 
 Socket.prototype.write = function(chunk, encoding, cb) {
-  if (typeof chunk !== 'string' && !Buffer.isBuffer(chunk))
+  if (!IS_STRING(chunk) && !IS_BUFFER(chunk))
     throw new TypeError('invalid data');
   return stream.Duplex.prototype.write.apply(this, arguments);
 };
@@ -650,7 +646,7 @@ Socket.prototype._writeGeneric = function(writev, data, encoding, cb) {
     // Retain chunks
     if (err === 0) req._chunks = chunks;
   } else {
-    var enc = Buffer.isBuffer(data) ? 'buffer' : encoding;
+    var enc = IS_BUFFER(data) ? 'buffer' : encoding;
     err = createWriteReq(req, this._handle, data, enc);
   }
 
@@ -732,14 +728,14 @@ Socket.prototype.__defineGetter__('bytesWritten', function() {
       encoding = this._pendingEncoding;
 
   state.buffer.forEach(function(el) {
-    if (Buffer.isBuffer(el.chunk))
+    if (IS_BUFFER(el.chunk))
       bytes += el.chunk.length;
     else
       bytes += Buffer.byteLength(el.chunk, el.encoding);
   });
 
   if (data) {
-    if (Buffer.isBuffer(data))
+    if (IS_BUFFER(data))
       bytes += data.length;
     else
       bytes += Buffer.byteLength(data, encoding);
@@ -817,7 +813,7 @@ Socket.prototype.connect = function(options, cb) {
   if (this.write !== Socket.prototype.write)
     this.write = Socket.prototype.write;
 
-  if (typeof options !== 'object') {
+  if (!IS_OBJECT(options)) {
     // Old API:
     // connect(port, [host], [cb])
     // connect(path, [cb]);
@@ -844,7 +840,7 @@ Socket.prototype.connect = function(options, cb) {
     initSocketHandle(this);
   }
 
-  if (typeof cb === 'function') {
+  if (IS_FUNCTION(cb)) {
     self.once('connect', cb);
   }
 
@@ -952,13 +948,13 @@ function Server(/* [ options, ] listener */) {
 
   var options;
 
-  if (typeof arguments[0] == 'function') {
+  if (IS_FUNCTION(arguments[0])) {
     options = {};
     self.on('connection', arguments[0]);
   } else {
     options = arguments[0] || {};
 
-    if (typeof arguments[1] == 'function') {
+    if (IS_FUNCTION(arguments[1])) {
       self.on('connection', arguments[1]);
     }
   }
@@ -998,7 +994,7 @@ var createServerHandle = exports._createServerHandle =
   // assign handle in listen, and clean up if bind or listen fails
   var handle;
 
-  if (typeof fd === 'number' && fd >= 0) {
+  if (IS_NUMBER(fd) && fd >= 0) {
     try {
       handle = createHandle(fd);
     }
@@ -1051,7 +1047,7 @@ Server.prototype._listen2 = function(address, port, addressType, backlog, fd) {
   if (!self._handle) {
     debug('_listen2: create a handle');
     var rval = createServerHandle(address, port, addressType, fd);
-    if (typeof rval === 'number') {
+    if (IS_NUMBER(rval)) {
       var error = errnoException(rval, 'listen');
       process.nextTick(function() {
         self.emit('error', error);
@@ -1126,7 +1122,7 @@ Server.prototype.listen = function() {
   var self = this;
 
   var lastArg = arguments[arguments.length - 1];
-  if (typeof lastArg == 'function') {
+  if (IS_FUNCTION(lastArg)) {
     self.once('listening', lastArg);
   }
 
@@ -1138,11 +1134,11 @@ Server.prototype.listen = function() {
 
   var TCP = process.binding('tcp_wrap').TCP;
 
-  if (arguments.length == 0 || typeof arguments[0] == 'function') {
+  if (arguments.length == 0 || IS_FUNCTION(arguments[0])) {
     // Bind to a random port.
     listen(self, '0.0.0.0', 0, null, backlog);
 
-  } else if (arguments[0] && typeof arguments[0] === 'object') {
+  } else if (arguments[0] && IS_OBJECT(arguments[0])) {
     var h = arguments[0];
     if (h._handle) {
       h = h._handle;
@@ -1152,7 +1148,7 @@ Server.prototype.listen = function() {
     if (h instanceof TCP) {
       self._handle = h;
       listen(self, null, -1, -1, backlog);
-    } else if (typeof h.fd === 'number' && h.fd >= 0) {
+    } else if (IS_NUMBER(h.fd) && h.fd >= 0) {
       listen(self, null, null, null, backlog, h.fd);
     } else {
       throw new Error('Invalid listen argument: ' + h);
@@ -1162,9 +1158,9 @@ Server.prototype.listen = function() {
     var pipeName = self._pipeName = arguments[0];
     listen(self, pipeName, -1, -1, backlog);
 
-  } else if (typeof arguments[1] == 'undefined' ||
-             typeof arguments[1] == 'function' ||
-             typeof arguments[1] == 'number') {
+  } else if (IS_UNDEFINED(arguments[1]) ||
+             IS_FUNCTION(arguments[1]) ||
+             IS_NUMBER(arguments[1])) {
     // The first argument is the port, no IP given.
     listen(self, '0.0.0.0', port, 4, backlog);
 
@@ -1351,11 +1347,11 @@ if (process.platform === 'win32') {
   var simultaneousAccepts;
 
   exports._setSimultaneousAccepts = function(handle) {
-    if (typeof handle === 'undefined') {
+    if (IS_UNDEFINED(handle)) {
       return;
     }
 
-    if (typeof simultaneousAccepts === 'undefined') {
+    if (IS_UNDEFINED(simultaneousAccepts)) {
       simultaneousAccepts = (process.env.NODE_MANY_ACCEPTS &&
                              process.env.NODE_MANY_ACCEPTS !== '0');
     }
diff --git a/lib/path.js b/lib/path.js
index 5cef72f..bd5e437 100644
--- a/lib/path.js
+++ b/lib/path.js
@@ -112,7 +112,7 @@ if (isWindows) {
       }
 
       // Skip empty and invalid entries
-      if (typeof path !== 'string') {
+      if (!IS_STRING(path)) {
         throw new TypeError('Arguments to path.resolve must be strings');
       } else if (!path) {
         continue;
@@ -214,7 +214,7 @@ if (isWindows) {
   // windows version
   exports.join = function() {
     function f(p) {
-      if (typeof p !== 'string') {
+      if (!IS_STRING(p)) {
         throw new TypeError('Arguments to path.join must be strings');
       }
       return p;
@@ -323,7 +323,7 @@ if (isWindows) {
       var path = (i >= 0) ? arguments[i] : process.cwd();
 
       // Skip empty and invalid entries
-      if (typeof path !== 'string') {
+      if (!IS_STRING(path)) {
         throw new TypeError('Arguments to path.resolve must be strings');
       } else if (!path) {
         continue;
@@ -374,7 +374,7 @@ if (isWindows) {
   exports.join = function() {
     var paths = Array.prototype.slice.call(arguments, 0);
     return exports.normalize(paths.filter(function(p, index) {
-      if (typeof p !== 'string') {
+      if (!IS_STRING(p)) {
         throw new TypeError('Arguments to path.join must be strings');
       }
       return p;
@@ -476,7 +476,7 @@ exports.existsSync = util.deprecate(function(path) {
 if (isWindows) {
   exports._makeLong = function(path) {
     // Note: this will *probably* throw somewhere.
-    if (typeof path !== 'string')
+    if (!IS_STRING(path))
       return path;
 
     if (!path) {
diff --git a/lib/querystring.js b/lib/querystring.js
index 0ab739a..ce9853d 100644
--- a/lib/querystring.js
+++ b/lib/querystring.js
@@ -114,33 +114,27 @@ QueryString.escape = function(str) {
 };
 
 var stringifyPrimitive = function(v) {
-  switch (typeof v) {
-    case 'string':
-      return v;
-
-    case 'boolean':
-      return v ? 'true' : 'false';
-
-    case 'number':
-      return isFinite(v) ? v : '';
-
-    default:
-      return '';
-  }
+  if (IS_STRING(v))
+    return v;
+  if (IS_BOOLEAN(v))
+    return v ? 'true' : 'false';
+  if (IS_NUMBER(v))
+    return isFinite(v) ? v : '';
+  return '';
 };
 
 
 QueryString.stringify = QueryString.encode = function(obj, sep, eq, name) {
   sep = sep || '&';
   eq = eq || '=';
-  if (obj === null) {
+  if (IS_NULL(obj)) {
     obj = undefined;
   }
 
-  if (typeof obj === 'object') {
+  if (IS_OBJECT(obj)) {
     return Object.keys(obj).map(function(k) {
       var ks = QueryString.escape(stringifyPrimitive(k)) + eq;
-      if (Array.isArray(obj[k])) {
+      if (IS_ARRAY(obj[k])) {
         return obj[k].map(function(v) {
           return ks + QueryString.escape(stringifyPrimitive(v));
         }).join(sep);
@@ -162,7 +156,7 @@ QueryString.parse = QueryString.decode = function(qs, sep, eq, options) {
   eq = eq || '=';
   var obj = {};
 
-  if (typeof qs !== 'string' || qs.length === 0) {
+  if (!IS_STRING(qs) || qs.length === 0) {
     return obj;
   }
 
@@ -170,7 +164,7 @@ QueryString.parse = QueryString.decode = function(qs, sep, eq, options) {
   qs = qs.split(sep);
 
   var maxKeys = 1000;
-  if (options && typeof options.maxKeys === 'number') {
+  if (options && IS_NUMBER(options.maxKeys)) {
     maxKeys = options.maxKeys;
   }
 
@@ -203,7 +197,7 @@ QueryString.parse = QueryString.decode = function(qs, sep, eq, options) {
 
     if (!hasOwnProperty(obj, k)) {
       obj[k] = v;
-    } else if (Array.isArray(obj[k])) {
+    } else if (IS_ARRAY(obj[k])) {
       obj[k].push(v);
     } else {
       obj[k] = [obj[k], v];
diff --git a/lib/readline.js b/lib/readline.js
index 3280115..f203530 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -63,13 +63,13 @@ function Interface(input, output, completer, terminal) {
 
   completer = completer || function() { return []; };
 
-  if (typeof completer !== 'function') {
+  if (!IS_FUNCTION(completer)) {
     throw new TypeError('Argument \'completer\' must be a function');
   }
 
   // backwards compat; check the isTTY prop of the output stream
   //  when `terminal` was not specified
-  if (typeof terminal == 'undefined') {
+  if (IS_UNDEFINED(terminal)) {
     terminal = !!output.isTTY;
   }
 
@@ -154,7 +154,7 @@ Interface.prototype.setPrompt = function(prompt) {
 
 
 Interface.prototype._setRawMode = function(mode) {
-  if (typeof this.input.setRawMode === 'function') {
+  if (IS_FUNCTION(this.input.setRawMode)) {
     return this.input.setRawMode(mode);
   }
 };
@@ -172,7 +172,7 @@ Interface.prototype.prompt = function(preserveCursor) {
 
 
 Interface.prototype.question = function(query, cb) {
-  if (typeof cb === 'function') {
+  if (IS_FUNCTION(cb)) {
     if (this._questionCallback) {
       this.prompt();
     } else {
@@ -290,7 +290,7 @@ Interface.prototype.write = function(d, key) {
 // \r\n, \n, or \r followed by something other than \n
 var lineEnding = /\r?\n|\r(?!\n)/;
 Interface.prototype._normalWrite = function(b) {
-  if (b === undefined) {
+  if (IS_UNDEFINED(b)) {
     return;
   }
   var string = this._decoder.write(b);
@@ -843,7 +843,7 @@ Interface.prototype._ttyWrite = function(s, key) {
         break;
 
       default:
-        if (Buffer.isBuffer(s))
+        if (IS_BUFFER(s))
           s = s.toString('utf-8');
 
         if (s) {
@@ -944,8 +944,8 @@ function emitKey(stream, s) {
       },
       parts;
 
-  if (Buffer.isBuffer(s)) {
-    if (s[0] > 127 && s[1] === undefined) {
+  if (IS_BUFFER(s)) {
+    if (s[0] > 127 && IS_UNDEFINED(s[1])) {
       s[0] -= 128;
       s = '\x1b' + s.toString(stream.encoding || 'utf-8');
     } else {
@@ -1124,7 +1124,7 @@ function emitKey(stream, s) {
   }
 
   // Don't emit a key if no name was found
-  if (key.name === undefined) {
+  if (IS_UNDEFINED(key.name)) {
     key = undefined;
   }
 
@@ -1143,13 +1143,13 @@ function emitKey(stream, s) {
  */
 
 function cursorTo(stream, x, y) {
-  if (typeof x !== 'number' && typeof y !== 'number')
+  if (!IS_NUMBER(x) && !IS_NUMBER(y))
     return;
 
-  if (typeof x !== 'number')
+  if (!IS_NUMBER(x))
     throw new Error("Can't set cursor row without also setting it's column");
 
-  if (typeof y !== 'number') {
+  if (!IS_NUMBER(y)) {
     stream.write('\x1b[' + (x + 1) + 'G');
   } else {
     stream.write('\x1b[' + (y + 1) + ';' + (x + 1) + 'H');
diff --git a/lib/repl.js b/lib/repl.js
index 5980bef..2fd5821 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -83,7 +83,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
   EventEmitter.call(this);
 
   var options, input, output, dom;
-  if (typeof prompt == 'object') {
+  if (IS_OBJECT(prompt)) {
     // an options object was given
     options = prompt;
     stream = options.stream || options.socket;
@@ -94,7 +94,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
     ignoreUndefined = options.ignoreUndefined;
     prompt = options.prompt;
     dom = options.domain;
-  } else if (typeof prompt != 'string') {
+  } else if (!IS_STRING(prompt)) {
     throw new Error('An options Object, or a prompt String are required');
   } else {
     options = {};
@@ -160,7 +160,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
   self.resetContext();
   self.bufferedCommand = '';
 
-  self.prompt = (prompt != undefined ? prompt : '> ');
+  self.prompt = !IS_UNDEFINED(prompt) ? prompt : '> ';
 
   function complete(text, callback) {
     self.complete(text, callback);
@@ -180,7 +180,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
   // figure out which "writer" function to use
   self.writer = options.writer || exports.writer;
 
-  if (typeof options.useColors === 'undefined') {
+  if (IS_UNDEFINED(options.useColors)) {
     options.useColors = rli.terminal;
   }
   self.useColors = !!options.useColors;
@@ -256,9 +256,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
                 function(e, ret) {
             if (e && !isSyntaxError(e)) return finish(e);
 
-            if (typeof ret === 'function' &&
-                /^[\r\n\s]*function/.test(evalCmd) ||
-                e) {
+            if (IS_FUNCTION(ret) && /^[\r\n\s]*function/.test(evalCmd) || e) {
               // Now as statement without parens.
               self.eval(evalCmd, self.context, 'repl', finish);
             } else {
@@ -300,7 +298,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
       self.bufferedCommand = '';
 
       // If we got any output - print it (if no error)
-      if (!e && (!self.ignoreUndefined || ret !== undefined)) {
+      if (!e && (!self.ignoreUndefined || !IS_UNDEFINED(ret))) {
         self.context._ = ret;
         self.outputStream.write(self.writer(ret) + '\n');
       }
@@ -422,7 +420,7 @@ var simpleExpressionRE =
 // getter code.
 REPLServer.prototype.complete = function(line, callback) {
   // There may be local variables to evaluate, try a nested REPL
-  if (this.bufferedCommand != undefined && this.bufferedCommand.length) {
+  if (!IS_UNDEFINED(this.bufferedCommand) && this.bufferedCommand.length) {
     // Get a new array of inputed lines
     var tmp = this.lines.slice();
     // Kill off all function declarations to push all local variables into
@@ -564,7 +562,7 @@ REPLServer.prototype.complete = function(line, callback) {
           this.eval('.scope', this.context, 'repl', function(err, globals) {
             if (err || !globals) {
               addStandardGlobals(completionGroups, filter);
-            } else if (Array.isArray(globals[0])) {
+            } else if (IS_ARRAY(globals[0])) {
               // Add grouped globals
               globals.forEach(function(group) {
                 completionGroups.push(group);
@@ -581,19 +579,19 @@ REPLServer.prototype.complete = function(line, callback) {
           // if (e) console.log(e);
 
           if (obj != null) {
-            if (typeof obj === 'object' || typeof obj === 'function') {
+            if (IS_OBJECT(obj) || IS_FUNCTION(obj)) {
               memberGroups.push(Object.getOwnPropertyNames(obj));
             }
             // works for non-objects
             try {
               var sentinel = 5;
               var p;
-              if (typeof obj === 'object' || typeof obj === 'function') {
+              if (IS_OBJECT(obj) || IS_FUNCTION(obj)) {
                 p = Object.getPrototypeOf(obj);
               } else {
                 p = obj.constructor ? obj.constructor.prototype : null;
               }
-              while (p !== null) {
+              while (!IS_NULL(p)) {
                 memberGroups.push(Object.getOwnPropertyNames(p));
                 p = Object.getPrototypeOf(p);
                 // Circular refs possible? Let's guard against that.
@@ -692,9 +690,9 @@ REPLServer.prototype.parseREPLKeyword = function(keyword, rest) {
 
 
 REPLServer.prototype.defineCommand = function(keyword, cmd) {
-  if (typeof cmd === 'function') {
+  if (IS_FUNCTION(cmd)) {
     cmd = {action: cmd};
-  } else if (typeof cmd.action !== 'function') {
+  } else if (!IS_FUNCTION(cmd.action)) {
     throw new Error('bad argument, action must be a function');
   }
   this.commands['.' + keyword] = cmd;
diff --git a/lib/smalloc.js b/lib/smalloc.js
index b0226a0..b6e9093 100644
--- a/lib/smalloc.js
+++ b/lib/smalloc.js
@@ -39,15 +39,15 @@ function alloc(n, obj) {
 
   if (n > kMaxLength)
     throw new RangeError('n > kMaxLength');
-  if (Array.isArray(obj))
+  if (IS_ARRAY(obj))
     throw new TypeError('Arrays are not supported');
 
-  return smalloc.alloc(obj === undefined ? {} : obj, n);
+  return smalloc.alloc(IS_UNDEFINED(obj) ? {} : obj, n);
 }
 
 
 function dispose(obj) {
-  if (obj instanceof Buffer)
+  if (IS_BUFFER(obj))
     throw new TypeError('obj cannot be a Buffer');
   smalloc.dispose(obj);
 }
diff --git a/lib/stream.js b/lib/stream.js
index 098ff61..5d8021e 100644
--- a/lib/stream.js
+++ b/lib/stream.js
@@ -84,7 +84,7 @@ Stream.prototype.pipe = function(dest, options) {
     if (didOnEnd) return;
     didOnEnd = true;
 
-    if (typeof dest.destroy === 'function') dest.destroy();
+    if (IS_FUNCTION(dest.destroy)) dest.destroy();
   }
 
   // don't leave dangling pipes when there are errors.
diff --git a/lib/tls.js b/lib/tls.js
index 6d2f59e..a0d31bf 100644
--- a/lib/tls.js
+++ b/lib/tls.js
@@ -51,7 +51,7 @@ exports.getCiphers = function() {
 // ("\x06spdy/2\x08http/1.1\x08http/1.0")
 exports.convertNPNProtocols = function convertNPNProtocols(NPNProtocols, out) {
   // If NPNProtocols is Array - translate it into buffer
-  if (Array.isArray(NPNProtocols)) {
+  if (IS_ARRAY(NPNProtocols)) {
     var buff = new Buffer(NPNProtocols.reduce(function(p, c) {
       return p + 1 + Buffer.byteLength(c);
     }, 0));
@@ -68,7 +68,7 @@ exports.convertNPNProtocols = function convertNPNProtocols(NPNProtocols, out) {
   }
 
   // If it's already a Buffer - store it
-  if (Buffer.isBuffer(NPNProtocols)) {
+  if (IS_BUFFER(NPNProtocols)) {
     out.NPNProtocols = NPNProtocols;
   }
 };
@@ -166,7 +166,7 @@ exports.checkServerIdentity = function checkServerIdentity(host, cert) {
     // RFC6125
     if (matchCN) {
       var commonNames = cert.subject.CN;
-      if (Array.isArray(commonNames)) {
+      if (IS_ARRAY(commonNames)) {
         for (var i = 0, k = commonNames.length; i < k; ++i) {
           dnsNames.push(regexpify(commonNames[i], true));
         }
@@ -194,7 +194,7 @@ exports.parseCertString = function parseCertString(s) {
       var key = parts[i].slice(0, sepIndex);
       var value = parts[i].slice(sepIndex + 1);
       if (key in out) {
-        if (!Array.isArray(out[key])) {
+        if (!IS_ARRAY(out[key])) {
           out[key] = [out[key]];
         }
         out[key].push(value);
diff --git a/lib/url.js b/lib/url.js
index 4903026..f10ba5f 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -94,7 +94,7 @@ var protocolPattern = /^([a-z0-9.+-]+:)/i,
     querystring = require('querystring');
 
 function urlParse(url, parseQueryString, slashesDenoteHost) {
-  if (url && typeof(url) === 'object' && url instanceof Url) return url;
+  if (url && IS_OBJECT(url) && url instanceof Url) return url;
 
   var u = new Url;
   u.parse(url, parseQueryString, slashesDenoteHost);
@@ -102,7 +102,7 @@ function urlParse(url, parseQueryString, slashesDenoteHost) {
 }
 
 Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
-  if (typeof url !== 'string') {
+  if (!IS_STRING(url)) {
     throw new TypeError("Parameter 'url' must be a string, not " + typeof url);
   }
 
@@ -340,7 +340,7 @@ function urlFormat(obj) {
   // If it's an obj, this is a no-op.
   // this way, you can call url_format() on strings
   // to clean up potentially wonky urls.
-  if (typeof(obj) === 'string') obj = urlParse(obj);
+  if (IS_STRING(obj)) obj = urlParse(obj);
   if (!(obj instanceof Url)) return Url.prototype.format.call(obj);
   return obj.format();
 }
@@ -370,8 +370,7 @@ Url.prototype.format = function() {
     }
   }
 
-  if (this.query && typeof this.query === 'object' &&
-      Object.keys(this.query).length) {
+  if (this.query && IS_OBJECT(this.query) && Object.keys(this.query).length) {
     query = querystring.stringify(this.query);
   }
 
@@ -414,7 +413,7 @@ function urlResolveObject(source, relative) {
 }
 
 Url.prototype.resolveObject = function(relative) {
-  if (typeof relative === 'string') {
+  if (IS_STRING(relative)) {
     var rel = new Url();
     rel.parse(relative, false, true);
     relative = rel;
@@ -554,7 +553,7 @@ Url.prototype.resolveObject = function(relative) {
     srcPath = srcPath.concat(relPath);
     result.search = relative.search;
     result.query = relative.query;
-  } else if (relative.search !== null && relative.search !== undefined) {
+  } else if (!IS_NULL_OR_UNDEFINED(relative.search)) {
     // just pull out the search.
     // like href='?foo'.
     // Put this after the other two cases because it simplifies the booleans
@@ -573,7 +572,7 @@ Url.prototype.resolveObject = function(relative) {
     result.search = relative.search;
     result.query = relative.query;
     //to support http.request
-    if (result.pathname !== null || result.search !== null) {
+    if (!IS_NULL(result.pathname) || !IS_NULL(result.search)) {
       result.path = (result.pathname ? result.pathname : '') +
                     (result.search ? result.search : '');
     }
@@ -667,7 +666,7 @@ Url.prototype.resolveObject = function(relative) {
   }
 
   //to support request.http
-  if (result.pathname !== null || result.search !== null) {
+  if (!IS_NULL(result.pathname) || !IS_NULL(result.search)) {
     result.path = (result.pathname ? result.pathname : '') +
                   (result.search ? result.search : '');
   }
diff --git a/lib/util.js b/lib/util.js
index fae4593..993e363 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -21,7 +21,7 @@
 
 var formatRegExp = /%[sdj%]/g;
 exports.format = function(f) {
-  if (typeof f !== 'string') {
+  if (!IS_STRING(f)) {
     var objects = [];
     for (var i = 0; i < arguments.length; i++) {
       objects.push(inspect(arguments[i]));
@@ -44,7 +44,7 @@ exports.format = function(f) {
     }
   });
   for (var x = args[i]; i < len; x = args[++i]) {
-    if (x === null || typeof x !== 'object') {
+    if (IS_NULL(x) || !IS_OBJECT(x)) {
       str += ' ' + x;
     } else {
       str += ' ' + inspect(x);
@@ -117,7 +117,7 @@ function inspect(obj, opts) {
   // legacy...
   if (arguments.length >= 3) ctx.depth = arguments[2];
   if (arguments.length >= 4) ctx.colors = arguments[3];
-  if (typeof opts === 'boolean') {
+  if (IS_BOOLEAN(opts)) {
     // legacy...
     ctx.showHidden = opts;
   } else if (opts) {
@@ -125,10 +125,10 @@ function inspect(obj, opts) {
     exports._extend(ctx, opts);
   }
   // set default options
-  if (typeof ctx.showHidden === 'undefined') ctx.showHidden = false;
-  if (typeof ctx.depth === 'undefined') ctx.depth = 2;
-  if (typeof ctx.colors === 'undefined') ctx.colors = false;
-  if (typeof ctx.customInspect === 'undefined') ctx.customInspect = true;
+  if (IS_UNDEFINED(ctx.showHidden)) ctx.showHidden = false;
+  if (IS_UNDEFINED(ctx.depth)) ctx.depth = 2;
+  if (IS_UNDEFINED(ctx.colors)) ctx.colors = false;
+  if (IS_UNDEFINED(ctx.customInspect)) ctx.customInspect = true;
   if (ctx.colors) ctx.stylize = stylizeWithColor;
   return formatValue(ctx, obj, ctx.depth);
 }
@@ -197,13 +197,15 @@ function arrayToHash(array) {
 function formatValue(ctx, value, recurseTimes) {
   // Provide a hook for user-specified inspect functions.
   // Check that value is an object with an inspect function on it
-  if (ctx.customInspect && value && typeof value.inspect === 'function' &&
+  if (ctx.customInspect &&
+      value &&
+      IS_FUNCTION(value.inspect) &&
       // Filter out the util module, it's inspect function is special
       value.inspect !== exports.inspect &&
       // Also filter out any prototype objects using the circular check.
       !(value.constructor && value.constructor.prototype === value)) {
     var ret = value.inspect(recurseTimes);
-    if ('string' !== typeof ret) {
+    if (!IS_STRING(ret)) {
       ret = formatValue(ctx, ret, recurseTimes);
     }
     return ret;
@@ -225,7 +227,7 @@ function formatValue(ctx, value, recurseTimes) {
 
   // Some type of object without properties can be shortcutted.
   if (keys.length === 0) {
-    if (typeof value === 'function') {
+    if (IS_FUNCTION(value)) {
       var name = value.name ? ': ' + value.name : '';
       return ctx.stylize('[Function' + name + ']', 'special');
     }
@@ -249,7 +251,7 @@ function formatValue(ctx, value, recurseTimes) {
   }
 
   // Make functions say that they are functions
-  if (typeof value === 'function') {
+  if (IS_FUNCTION(value)) {
     var n = value.name ? ': ' + value.name : '';
     base = ' [Function' + n + ']';
   }
@@ -299,26 +301,21 @@ function formatValue(ctx, value, recurseTimes) {
 
 
 function formatPrimitive(ctx, value) {
-  switch (typeof value) {
-    case 'undefined':
-      return ctx.stylize('undefined', 'undefined');
-
-    case 'string':
-      var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
-                                               .replace(/'/g, "\\'")
-                                               .replace(/\\"/g, '"') + '\'';
-      return ctx.stylize(simple, 'string');
-
-    case 'number':
-      return ctx.stylize('' + value, 'number');
-
-    case 'boolean':
-      return ctx.stylize('' + value, 'boolean');
-  }
+  if (IS_UNDEFINED(value))
+    return ctx.stylize('undefined', 'undefined');
+  if (IS_STRING(value)) {
+    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
+                                             .replace(/'/g, "\\'")
+                                             .replace(/\\"/g, '"') + '\'';
+    return ctx.stylize(simple, 'string');
+  }
+  if (IS_NUMBER(value))
+    return ctx.stylize('' + value, 'number');
+  if (IS_BOOLEAN(value))
+    return ctx.stylize('' + value, 'boolean');
   // For some reason typeof null is "object", so special case here.
-  if (value === null) {
+  if (IS_NULL(value))
     return ctx.stylize('null', 'null');
-  }
 }
 
 
@@ -366,7 +363,7 @@ function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
   }
   if (!str) {
     if (ctx.seen.indexOf(desc.value) < 0) {
-      if (recurseTimes === null) {
+      if (IS_NULL(recurseTimes)) {
         str = formatValue(ctx, desc.value, null);
       } else {
         str = formatValue(ctx, desc.value, recurseTimes - 1);
@@ -386,7 +383,7 @@ function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
       str = ctx.stylize('[Circular]', 'special');
     }
   }
-  if (typeof name === 'undefined') {
+  if (IS_UNDEFINED(name)) {
     if (array && key.match(/^\d+$/)) {
       return str;
     }
@@ -430,25 +427,25 @@ function reduceToSingleString(output, base, braces) {
 // NOTE: These type checking functions intentionally don't use `instanceof`
 // because it is fragile and can be easily faked with `Object.create()`.
 function isArray(ar) {
-  return Array.isArray(ar);
+  return IS_ARRAY(ar);
 }
 exports.isArray = isArray;
 
 
 function isRegExp(re) {
-  return typeof re === 'object' && objectToString(re) === '[object RegExp]';
+  return IS_OBJECT(re) && objectToString(re) === '[object RegExp]';
 }
 exports.isRegExp = isRegExp;
 
 
 function isDate(d) {
-  return typeof d === 'object' && objectToString(d) === '[object Date]';
+  return IS_OBJECT(d) && objectToString(d) === '[object Date]';
 }
 exports.isDate = isDate;
 
 
 function isError(e) {
-  return typeof e === 'object' && objectToString(e) === '[object Error]';
+  return IS_OBJECT(e) && objectToString(e) === '[object Error]';
 }
 exports.isError = isError;
 
@@ -509,7 +506,7 @@ exports.inherits = function(ctor, superCtor) {
 
 exports._extend = function(origin, add) {
   // Don't do anything if add isn't an object
-  if (!add || typeof add !== 'object') return origin;
+  if (!add || !IS_OBJECT(add)) return origin;
 
   var keys = Object.keys(add);
   var i = keys.length;
@@ -604,7 +601,7 @@ exports.pump = exports.deprecate(function(readStream, writeStream, callback) {
 
 var uv;
 exports._errnoException = function(err, syscall) {
-  if (typeof uv === 'undefined') uv = process.binding('uv');
+  if (IS_UNDEFINED(uv)) uv = process.binding('uv');
   var errname = uv.errname(err);
   var e = new Error(syscall + ' ' + errname);
   e.code = errname;
diff --git a/lib/vm.js b/lib/vm.js
index eb17cc0..f521444 100644
--- a/lib/vm.js
+++ b/lib/vm.js
@@ -33,7 +33,7 @@ function Script(code, ctx, filename) {
 
   // bind all methods to this Script object
   Object.keys(binding.NodeScript.prototype).forEach(function(f) {
-    if (typeof binding.NodeScript.prototype[f] === 'function') {
+    if (IS_FUNCTION(binding.NodeScript.prototype[f])) {
       this[f] = function() {
         if (!(this instanceof Script)) {
           throw new TypeError('invalid call to ' + f);
diff --git a/lib/zlib.js b/lib/zlib.js
index e41d27a..855df06 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -108,7 +108,7 @@ exports.createUnzip = function(o) {
 // Convenience methods.
 // compress/decompress a string or buffer in one step.
 exports.deflate = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -116,7 +116,7 @@ exports.deflate = function(buffer, opts, callback) {
 };
 
 exports.gzip = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -124,7 +124,7 @@ exports.gzip = function(buffer, opts, callback) {
 };
 
 exports.deflateRaw = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -132,7 +132,7 @@ exports.deflateRaw = function(buffer, opts, callback) {
 };
 
 exports.unzip = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -140,7 +140,7 @@ exports.unzip = function(buffer, opts, callback) {
 };
 
 exports.inflate = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -148,7 +148,7 @@ exports.inflate = function(buffer, opts, callback) {
 };
 
 exports.gunzip = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -156,7 +156,7 @@ exports.gunzip = function(buffer, opts, callback) {
 };
 
 exports.inflateRaw = function(buffer, opts, callback) {
-  if (typeof opts === 'function') {
+  if (IS_FUNCTION(opts)) {
     callback = opts;
     opts = {};
   }
@@ -305,7 +305,7 @@ function Zlib(opts, mode) {
   }
 
   if (opts.dictionary) {
-    if (!Buffer.isBuffer(opts.dictionary)) {
+    if (!IS_BUFFER(opts.dictionary)) {
       throw new Error('Invalid dictionary: it should be a Buffer instance');
     }
   }
@@ -327,10 +327,10 @@ function Zlib(opts, mode) {
   };
 
   var level = exports.Z_DEFAULT_COMPRESSION;
-  if (typeof opts.level === 'number') level = opts.level;
+  if (IS_NUMBER(opts.level)) level = opts.level;
 
   var strategy = exports.Z_DEFAULT_STRATEGY;
-  if (typeof opts.strategy === 'number') strategy = opts.strategy;
+  if (IS_NUMBER(opts.strategy)) strategy = opts.strategy;
 
   this._binding.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
                      level,
@@ -390,7 +390,7 @@ Zlib.prototype._flush = function(callback) {
 Zlib.prototype.flush = function(kind, callback) {
   var ws = this._writableState;
 
-  if (typeof kind === 'function' || (kind === undefined && !callback)) {
+  if (IS_FUNCTION(kind) || (IS_UNDEFINED(kind) && !callback)) {
     callback = kind;
     kind = binding.Z_FULL_FLUSH;
   }
@@ -435,7 +435,7 @@ Zlib.prototype._transform = function(chunk, encoding, cb) {
   var ending = ws.ending || ws.ended;
   var last = ending && (!chunk || ws.length === chunk.length);
 
-  if (chunk !== null && !Buffer.isBuffer(chunk))
+  if (!IS_NULL(chunk) && !IS_BUFFER(chunk))
     return cb(new Error('invalid input'));
 
   // If it's the last chunk, or a final flush, we use the Z_FINISH flush flag.
diff --git a/node.gyp b/node.gyp
index a6f7256..ecf21f2 100644
--- a/node.gyp
+++ b/node.gyp
@@ -388,6 +388,7 @@
             '<(python)',
             'tools/js2c.py',
             '<@(_outputs)',
+            'src/macros.py',
             '<@(_inputs)',
           ],
         },
diff --git a/src/macros.py b/src/macros.py
new file mode 100644
index 0000000..39d05c9
--- /dev/null
+++ b/src/macros.py
@@ -0,0 +1,16 @@
+macro IS_BOOLEAN(arg)           = (typeof(arg) === 'boolean');
+macro IS_NULL(arg)              = (arg === null);
+macro IS_NULL_OR_UNDEFINED(arg) = (arg == null);
+macro IS_NUMBER(arg)            = (typeof(arg) === 'number');
+macro IS_STRING(arg)            = (typeof(arg) === 'string');
+macro IS_SYMBOL(arg)            = (typeof(arg) === 'symbol');
+macro IS_UNDEFINED(arg)         = (typeof(arg) === 'undefined');
+
+# These macros follow the semantics of V8's %_Is*() functions.
+macro IS_ARRAY(arg)             = (Array.isArray(arg));
+macro IS_DATE(arg)              = ((arg) instanceof Date);
+macro IS_FUNCTION(arg)          = (typeof(arg) === 'function');
+macro IS_OBJECT(arg)            = (typeof(arg) === 'object');
+macro IS_REGEXP(arg)            = ((arg) instanceof RegExp);
+
+macro IS_BUFFER(arg)            = ((arg) instanceof Buffer);