async - npm Package Compare versions

Comparing version 0.2.3 to 0.2.4

lib/async.js

@@ -918,2 +918,20 @@ /*global setImmediate: false, setTimeout: false, console: false */
 
+    async.compose = function (/* functions... */) {
+        var fns = Array.prototype.reverse.call(arguments);
+        return function () {
+            var that = this;
+            var args = Array.prototype.slice.call(arguments);
+            var callback = args.pop();
+            async.reduce(fns, args, function (newargs, fn, cb) {
+                fn.apply(that, newargs.concat([function () {
+                    var err = arguments[0];
+                    var nextargs = Array.prototype.slice.call(arguments, 1);
+                    cb(err, nextargs);
+                }]))
+            },
+            function (err, results) {
+                callback.apply(that, [err].concat(results));
+            });
+        };
+    };
 
@@ -920,0 +938,0 @@ // AMD / RequireJS

package.json

@@ -6,3 +6,3 @@ {
     "author": "Caolan McMahon",
-    "version": "0.2.3",
+    "version": "0.2.4",
     "repository" : {
@@ -9,0 +9,0 @@ "type" : "git",

README.md

@@ -95,2 +95,3 @@ # Async.js
 * [waterfall](#waterfall)
+* [compose](#compose)
 * [queue](#queue)
@@ -163,10 +164,13 @@ * [cargo](#cargo)
 
-The same as forEach only the iterator is applied to batches of items in the
-array, in series. The next batch of iterators is only called once the current
-one has completed processing.
+The same as forEach only no more than "limit" iterators will be simultaneously 
+running at any time.
 
+Note that the items are not processed in batches, so there is no guarantee that
+ the first "limit" iterator functions will complete before any others are 
+started.
+
 __Arguments__
 
 * arr - An array to iterate over.
-* limit - How many items should be in each batch.
+* limit - The maximum number of iterators to run at any time.
 * iterator(item, callback) - A function to apply to each item in the array.
@@ -239,10 +243,13 @@ The iterator is passed a callback which must be called once it has completed.
 
-The same as map only the iterator is applied to batches of items in the
-array, in series. The next batch of iterators is only called once the current
-one has completed processing.
+The same as map only no more than "limit" iterators will be simultaneously 
+running at any time.
 
+Note that the items are not processed in batches, so there is no guarantee that
+ the first "limit" iterator functions will complete before any others are 
+started.
+
 __Arguments__
 
 * arr - An array to iterate over.
-* limit - How many items should be in each batch.
+* limit - The maximum number of iterators to run at any time.
 * iterator(item, callback) - A function to apply to each item in the array.
@@ -676,2 +683,5 @@ The iterator is passed a callback which must be called once it has completed.
 
+Note that the tasks are not executed in batches, so there is no guarantee that 
+the first "limit" tasks will complete before any others are started.
+
 __Arguments__
@@ -785,3 +795,41 @@
 ---------------------------------------
+<a name="compose" />
+### compose(fn1, fn2...)
 
+Creates a function which is a composition of the passed asynchronous
+functions. Each function consumes the return value of the function that
+follows. Composing functions f(), g() and h() would produce the result of
+f(g(h())), only this version uses callbacks to obtain the return values.
+
+Each function is executed with the `this` binding of the composed function.
+
+__Arguments__
+
+* functions... - the asynchronous functions to compose
+
+
+__Example__
+
+```js
+function add1(n, callback) {
+    setTimeout(function () [
+        callback(null, n + 1);
+    }, 10);
+}
+
+function mul3(n, callback) {
+    setTimeout(function () [
+        callback(null, n * 3);
+    }, 10);
+}
+
+var add1mul3 = async.compose(mul3, add1);
+
+add1mul3(4, function (err, result) {
+   // result now equals 15
+});
+```
+
+---------------------------------------
+
 <a name="queue" />
@@ -788,0 +836,0 @@ ### queue(worker, concurrency)

No alert changes

Improved metrics

Total package byte prevSize

118664

increased by75.64%

Number of package files

5

increased by25%

Lines of code

883

increased by2.08%

Number of lines in readme file

1294

increased by3.85%

No dependency changes