throw new Error(msg);
}
}
+
+/**
+ * Call this from places in the code that should never be reached.
+ *
+ * For example, handling all the values of enum with a switch() like this:
+ *
+ * function getValueFromEnum(enum) {
+ * switch (enum) {
+ * case ENUM_FIRST_OF_TWO:
+ * return first
+ * case ENUM_LAST_OF_TWO:
+ * return last;
+ * }
+ * assertNotReached();
+ * return document;
+ * }
+ *
+ * This code should only be hit in the case of serious programmer error or
+ * unexpected input.
+ *
+ * @param {string=} opt_message A message to show when this is hit.
+ */
+function assertNotReached(opt_message) {
+ throw new Error(opt_message || "Unreachable code hit");
+}