.map callback called async (closes #1148)

src/map.js

@@ -10,6 +10,7 @@ var getDomain = Promise._getDomain;
 var util = require("./util");
 var tryCatch = util.tryCatch;
 var errorObj = util.errorObj;
+var async = Promise._async;
 
 function MappingPromiseArray(promises, fn, limit, _filter) {
     this.constructor$(promises);
@@ -22,10 +23,14 @@ function MappingPromiseArray(promises, fn, limit, _filter) {
     this._limit = limit;
     this._inFlight = 0;
     this._queue = [];
-    this._init$(undefined, RESOLVE_ARRAY);
+    async.invoke(this._asyncInit, this, undefined);
 }
 util.inherits(MappingPromiseArray, PromiseArray);
 
+MappingPromiseArray.prototype._asyncInit = function() {
+    this._init$(undefined, RESOLVE_ARRAY);
+};
+
 // The following hack is required because the super constructor
 // might call promiseFulfilled before this.callback = fn is set
 //

test/mocha/map.js

@@ -111,6 +111,48 @@ describe("Promise.map-test", function () {
             }
         );
     });
+
+    specify("should call mapper asynchronously on values array", function() {
+        var calls = 0;
+        function mapper(val) {
+            calls++;
+        }
+
+        var input = [1, 2, 3];
+        var p = Promise.map(input, mapper);
+        assert(calls === 0);
+        return p.then(function() {
+            assert(calls === 3);
+        });
+    });
+
+    specify("should call mapper asynchronously on promises array", function() {
+        var calls = 0;
+        function mapper(val) {
+            calls++;
+        }
+
+        var input = [Promise.resolve(1), Promise.resolve(2), Promise.resolve(3)];
+        var p = Promise.map(input, mapper);
+        assert(calls === 0);
+        return p.then(function() {
+            assert(calls === 3);
+        });
+    });
+
+    specify("should call mapper asynchronously on mixed array", function() {
+        var calls = 0;
+        function mapper(val) {
+            calls++;
+        }
+
+        var input = [1, Promise.resolve(2), 3];
+        var p = Promise.map(input, mapper);
+        assert(calls === 0);
+        return p.then(function() {
+            assert(calls === 3);
+        });
+    });
 });
 
 describe("Promise.map-test with concurrency", function () {