add applyEach function

3 files changed, 110 insertions, 0 deletions

diff --git a/README.md b/README.md
index 2535cf8..9927c98 100644
--- a/README.md
+++ b/README.md
@@ -93,6 +93,7 @@ So far its been tested in IE6, IE7, IE8, FF3.6 and Chrome 5. Usage:
 * [doUntil](#doUntil)
 * [waterfall](#waterfall)
 * [compose](#compose)
+* [applyEach](#applyEach)
 * [queue](#queue)
 * [cargo](#cargo)
 * [auto](#auto)
@@ -833,6 +834,36 @@ add1mul3(4, function (err, result) {
 ```
 
 ---------------------------------------
+<a name="applyEach" />
+### applyEach(fns, args..., callback)
+
+Applies the provided arguments to each function in the array, calling the
+callback after all functions have completed. If you only provide the first
+argument then it will return a function which lets you pass in the
+arguments as if it were a single function call.
+
+__Arguments__
+
+* fns - the asynchronous functions to all call with the same arguments
+* args... - any number of separate arguments to pass to the function
+* callback - the final argument should be the callback, called when all
+  functions have completed processing
+
+
+__Example__
+
+```js
+async.applyEach([enableSearch, updateSchema], 'bucket', callback);
+
+// partial application example:
+async.each(
+    buckets,
+    async.applyEach([enableSearch, updateSchema]),
+    callback
+);
+```
+
+---------------------------------------
 
 <a name="queue" />
 ### queue(worker, concurrency)
diff --git a/lib/async.js b/lib/async.js
index a805447..ad3982a 100755
--- a/lib/async.js
+++ b/lib/async.js
@@ -945,6 +945,25 @@
         };
     };
 
+    async.applyEach = function (fns /*args...*/) {
+        var go = function () {
+            var that = this;
+            var args = Array.prototype.slice.call(arguments);
+            var callback = args.pop();
+            return async.each(fns, function (fn, cb) {
+                fn.apply(that, args.concat([cb]));
+            },
+            callback);
+        };
+        if (arguments.length > 1) {
+            var args = Array.prototype.slice.call(arguments, 1);
+            return go.apply(this, args);
+        }
+        else {
+            return go;
+        }
+    };
+
     // AMD / RequireJS
     if (typeof define !== 'undefined' && define.amd) {
         define([], function () {
diff --git a/test/test-async.js b/test/test-async.js
index 1caf1bc..5bd72bf 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -66,6 +66,66 @@ function getFunctionsObject(call_order) {
     };
 }
 
+exports['applyEach'] = function (test) {
+    test.expect(4);
+    var call_order = [];
+    var one = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('one');
+            cb(null, 1);
+        }, 100);
+    };
+    var two = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('two');
+            cb(null, 2);
+        }, 50);
+    };
+    var three = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('three');
+            cb(null, 3);
+        }, 150);
+    };
+    async.applyEach([one, two, three], 5, function (err) {
+        test.same(call_order, ['two', 'one', 'three']);
+        test.done();
+    });
+};
+
+exports['applyEach partial application'] = function (test) {
+    test.expect(4);
+    var call_order = [];
+    var one = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('one');
+            cb(null, 1);
+        }, 100);
+    };
+    var two = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('two');
+            cb(null, 2);
+        }, 50);
+    };
+    var three = function (val, cb) {
+        test.equal(val, 5);
+        setTimeout(function () {
+            call_order.push('three');
+            cb(null, 3);
+        }, 150);
+    };
+    async.applyEach([one, two, three])(5, function (err) {
+        test.same(call_order, ['two', 'one', 'three']);
+        test.done();
+    });
+};
+
 exports['compose'] = function (test) {
     test.expect(4);
     var add2 = function (n, cb) {