Promise.all and race should work with iterables

src/promise.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Object = global.Object
 // var $WeakMap = global.WeakMap
@@ skipping 283 matching lines @@
     );
   }
 
   // Combinators.
 
   function PromiseCast(x) {
     // TODO(rossberg): cannot do better until we support @@create.
     return IsPromise(x) ? x : new this(function(resolve) { resolve(x) });
   }
 
-  function PromiseAll(values) {
+  function PromiseAll(iterable) {
     var deferred = %_CallFunction(this, PromiseDeferred);
     var resolutions = [];
-    if (!%_IsArray(values)) {
-      deferred.reject(MakeTypeError('invalid_argument'));
-      return deferred.promise;
-    }
     try {
-      var count = values.length;
+      var count = 0;
+      var i = 0;
+      for (var value of iterable) {
+        this.resolve(value).then(
+            // Nested scope to get closure over current i (and avoid .bind).

[arv (Not doing code reviews), 2015/02/23 16:40:39]

Andreas, do you think it would make sense to switch to let at  this point?

[rossberg, 2015/02/23 17:38:40]

Probably. The comment is outdated either way, because after this change, i is no
longer a loop variable. For-let won't help any more, you'd need to use an
explicit let binding in the loop body.

[arv (Not doing code reviews), 2015/02/23 17:42:45]

Yup.

I'll make the change... scratch that. Builtins cannot yet use harmony scoping.

+            // TODO(rossberg): Use for-let instead once available.
+            (function(i) {
+              return function(x) {
+                resolutions[i] = x;
+                if (--count === 0) deferred.resolve(resolutions);
+              }
+            })(i),
+            function(r) { deferred.reject(r); });
+        ++i;
+        ++count;
+      }
+
       if (count === 0) {
         deferred.resolve(resolutions);
-      } else {
-        for (var i = 0; i < values.length; ++i) {
-          this.resolve(values[i]).then(
-            (function() {
-              // Nested scope to get closure over current i (and avoid .bind).
-              // TODO(rossberg): Use for-let instead once available.
-              var i_captured = i;
-              return function(x) {
-                resolutions[i_captured] = x;
-                if (--count === 0) deferred.resolve(resolutions);
-              };
-            })(),
-            function(r) { deferred.reject(r) }
-          );
-        }
       }
+
     } catch (e) {
       deferred.reject(e)
     }
     return deferred.promise;
   }
 
-  function PromiseOne(values) {
+  function PromiseRace(iterable) {
     var deferred = %_CallFunction(this, PromiseDeferred);
-    if (!%_IsArray(values)) {
-      deferred.reject(MakeTypeError('invalid_argument'));
-      return deferred.promise;
-    }
     try {
-      for (var i = 0; i < values.length; ++i) {
-        this.resolve(values[i]).then(
-          function(x) { deferred.resolve(x) },
-          function(r) { deferred.reject(r) }
-        );
+      for (var value of iterable) {
+        this.resolve(value).then(
+            function(x) { deferred.resolve(x) },
+            function(r) { deferred.reject(r) });
       }
     } catch (e) {
       deferred.reject(e)
     }
     return deferred.promise;
   }
 
 
   // Utility for debugger
 
@@ skipping 22 matching lines @@
 
   %CheckIsBootstrapping();
   %AddNamedProperty(global, 'Promise', $Promise, DONT_ENUM);
   %AddNamedProperty(
       $Promise.prototype, symbolToStringTag, "Promise", DONT_ENUM | READ_ONLY);
   InstallFunctions($Promise, DONT_ENUM, [
     "defer", PromiseDeferred,
     "accept", PromiseResolved,
     "reject", PromiseRejected,
     "all", PromiseAll,
-    "race", PromiseOne,
+    "race", PromiseRace,
     "resolve", PromiseCast
   ]);
   InstallFunctions($Promise.prototype, DONT_ENUM, [
     "chain", PromiseChain,
     "then", PromiseThen,
     "catch", PromiseCatch
   ]);
 
 })();