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28 // Flags: --harmony-proxies
30 // Test for-of semantics.
35 // First, some helpers.
38 for (var i = 0; i < arguments.length; i++) {
43 function wrap_iterator(iterator) {
45 iterable[Symbol.iterator] = function() { return iterator; };
49 function integers_until(max) {
51 var ret = { value: this.n, done: this.n == max };
55 return wrap_iterator({ next: next, n: 0 });
58 function results(results) {
63 return wrap_iterator({ next: next });
66 function* integers_from(n) {
70 // A destructive append.
71 function append(x, tail) {
72 tail[tail.length] = x;
76 function sum(x, tail) {
80 function fold(cons, seed, iterable) {
81 for (var x of iterable) {
87 function* take(iterable, n) {
89 for (let x of iterable) {
95 function nth(iterable, n) {
96 for (let x of iterable) {
97 if (n-- == 0) return x;
102 function* skip_every(iterable, n) {
104 for (let x of iterable) {
105 if (++i % n == 0) continue;
110 function* iter_map(iterable, f) {
111 for (var x of iterable) {
115 function nested_fold(cons, seed, iterable) {
117 for (let x of iterable) {
119 seed = cons(y, seed);
125 function* unreachable(iterable) {
126 for (let x of iterable) {
131 function one_time_getter(o, prop, val) {
132 function set_never() { throw "unreachable"; }
134 function get_once() {
135 if (gotten) throw "got twice";
139 Object.defineProperty(o, prop, {get: get_once, set: set_never})
143 function never_getter(o, prop) {
144 function never() { throw "unreachable"; }
145 Object.defineProperty(o, prop, {get: never, set: never})
149 function remove_next_after(iterable, n) {
150 var iterator = iterable[Symbol.iterator]();
152 if (n-- == 0) delete this.next;
153 return iterator.next();
155 return wrap_iterator({ next: next });
158 function poison_next_after(iterable, n) {
159 var iterator = iterable[Symbol.iterator]();
161 return iterator.next();
163 function next_getter() {
169 Object.defineProperty(o, 'next', { get: next_getter });
170 return wrap_iterator(o);
175 // Non-generator iterators.
176 assertEquals(45, fold(sum, 0, integers_until(10)));
177 // Generator iterators.
178 assertEquals([1, 2, 3], fold(append, [], values(1, 2, 3)));
180 assertEquals(45, fold(sum, 0, take(integers_from(0), 10)));
182 assertEquals(90, fold(sum, 0, take(skip_every(integers_from(0), 2), 10)));
184 assertEquals(10, nth(integers_from(0), 10));
186 assertEquals([0, 0, 1, 0, 1, 2, 0, 1, 2, 3],
189 iter_map(integers_until(5), integers_until)));
190 // Result objects with sparse fields.
191 assertEquals([undefined, 1, 2, 3],
193 results([{ done: false },
194 { value: 1, done: false },
195 // A missing "done" is the same as undefined, which
199 { value: 3, done: 0 },
201 { value: 4, done: 42 }])));
202 // Results that are not objects.
203 assertThrows(function() {
204 assertEquals([undefined, undefined, undefined],
206 results([10, "foo", /qux/, { value: 37, done: true }])));
208 // Getters (shudder).
211 results([one_time_getter({ value: 1 }, 'done', false),
212 one_time_getter({ done: false }, 'value', 2),
213 { value: 37, done: true },
214 never_getter(never_getter({}, 'done'), 'value')])));
216 // Unlike the case with for-in, null and undefined cause an error.
217 assertThrows('fold(sum, 0, unreachable(null))', TypeError);
218 assertThrows('fold(sum, 0, unreachable(undefined))', TypeError);
220 // Other non-iterators do cause an error.
221 assertThrows('fold(sum, 0, unreachable({}))', TypeError);
222 assertThrows('fold(sum, 0, unreachable(false))', TypeError);
223 assertThrows('fold(sum, 0, unreachable(37))', TypeError);
225 // "next" is looked up each time.
226 assertThrows('fold(sum, 0, remove_next_after(integers_until(10), 5))',
228 // It is not called at any other time.
230 fold(sum, 0, remove_next_after(integers_until(10), 10)));
231 // It is not looked up too many times.
233 fold(sum, 0, poison_next_after(integers_until(10), 10)));
235 function labelled_continue(iterable) {
240 for (var x of iterable) continue outer;
245 assertEquals(11, labelled_continue(integers_until(10)));
247 function labelled_break(iterable) {
252 for (var x of iterable) break outer;
256 assertEquals(1, labelled_break(integers_until(10)));
258 // Test continue/break in catch.
259 function catch_control(iterable, k) {
261 for (var x of iterable) {
265 if (e == "continue") continue;
266 else if (e == "break") break;
273 catch_control(integers_until(10),
274 function() { throw "break" }));
276 catch_control(integers_until(10),
277 function() { throw "continue" }));
279 catch_control(integers_until(10),
281 if (x == 5) return x;
285 // Test continue/break in try.
286 function try_control(iterable, k) {
288 for (var x of iterable) {
291 if (e == "continue") continue;
292 else if (e == "break") break;
301 try_control(integers_until(10),
302 function() { return "break" }));
304 try_control(integers_until(10),
305 function() { return "continue" }));
307 try_control(integers_until(10),
308 function(x) { return (x == 5) ? x : "continue" }));
310 // Proxy results, with getters.
311 function transparent_proxy(x) {
312 return Proxy.create({
313 get: function(receiver, name) { return x[name]; }
318 results([one_time_getter({ value: 1 }, 'done', false),
319 one_time_getter({ done: false }, 'value', 2),
320 { value: 37, done: true },
321 never_getter(never_getter({}, 'done'), 'value')]
322 .map(transparent_proxy))));
325 function poison_proxy_after(iterable, n) {
326 var iterator = iterable[Symbol.iterator]();
327 return wrap_iterator(Proxy.create({
328 get: function(receiver, name) {
329 if (name == 'next' && n-- < 0) throw "unreachable";
330 return iterator[name];
332 // Needed for integers_until(10)'s this.n++.
333 set: function(receiver, name, val) {
334 return iterator[name] = val;
338 assertEquals(45, fold(sum, 0, poison_proxy_after(integers_until(10), 10)));
341 function test_iterator_result_object_non_object(value, descr) {
344 var message = 'Iterator result ' + (descr || value) + ' is not an object';
347 results([{value: 1}, {}, value, {value: 2}, {done: true}]));
351 assertInstanceof(ex, TypeError);
352 assertEquals(message, ex.message);
353 assertArrayEquals([1, undefined], arr);
355 test_iterator_result_object_non_object(null);
356 test_iterator_result_object_non_object(undefined);
357 test_iterator_result_object_non_object(42);
358 test_iterator_result_object_non_object('abc');
359 test_iterator_result_object_non_object(false);
360 test_iterator_result_object_non_object(Symbol('x'), 'Symbol(x)');