[Pkg-javascript-commits] [node-async] 40/480: added the concat function

[Jonas Smedegaard]

This is an automated email from the git hooks/post-receive script.

js pushed a commit to branch master
in repository node-async.

commit 263f71f52d6f8d0b73d47223c6e761c06de90b21
Author: Caolan McMahon <caolan at caolanmcmahon.com>
Date:   Thu Sep 16 10:21:46 2010 +0100

    added the concat function
---
 README.md          | 32 ++++++++++++++++++++++++++++----
 lib/async.js       | 12 ++++++++++++
 test/test-async.js | 28 ++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 0ea8e8b..eae3cd6 100644
--- a/README.md
+++ b/README.md
@@ -99,6 +99,9 @@ some
 every
 : Returns true if every element in the array satisfies an async test.
 
+concat
+: Apply an iterator to each item in a list and concatenate the results.
+
 
 ### Flow Control
 
@@ -268,7 +271,7 @@ reducing it then its probably a good idea to do so.
 
 __Arguments__
 
-* arr - An array to iterator over.
+* arr - An array to iterate over.
 * memo - The initial state of the reduction.
 * iterator(memo, item, callback) - A function applied to each item in the
   array to produce the next step in the reduction. The iterator is passed a
@@ -308,7 +311,7 @@ If order within the original array is important then look at detectSeries.
 
 __Arguments__
 
-* arr - An array to iterator over.
+* arr - An array to iterate over.
 * iterator(item, callback) - A truth test to apply to each item in the array.
   The iterator is passed a callback which must be called once it has completed.
 * callback(result) - A callback which is called as soon as any iterator returns
@@ -367,7 +370,7 @@ call returns true, the main callback is immediately called.
 
 __Arguments__
 
-* arr - An array to iterator over.
+* arr - An array to iterate over.
 * iterator(item, callback) - A truth test to apply to each item in the array.
   The iterator is passed a callback which must be called once it has completed.
 * callback(result) - A callback which is called as soon as any iterator returns
@@ -391,7 +394,7 @@ way node libraries work with truth tests like path.exists.
 
 __Arguments__
 
-* arr - An array to iterator over.
+* arr - An array to iterate over.
 * iterator(item, callback) - A truth test to apply to each item in the array.
   The iterator is passed a callback which must be called once it has completed.
 * callback(result) - A callback which is called after all the iterator
@@ -404,6 +407,27 @@ __Example__
         // if result is true then every file exists
     });
 
+### concat(arr, iterator, callback)
+
+Applies an iterator to each item in a list, concatenating the results. Returns the
+concatenated list.
+
+__Arguments__
+
+* arr - An array to iterate over
+* iterator(item, callback) - A function to apply to each item in the array.
+  The iterator is passed a callback which must be called once it has completed
+  with an error (which can be null) and an array of results.
+* callback(err, results) - A callback which is called after all the iterator
+  functions have finished, or an error has occurred. Results is an array containing
+  the concatenated results of the iterator function.
+
+__Example__
+
+    async.concat(['dir1','dir2','dir3'], fs.readdir, function(err, files){
+        // files is now a list of filenames that exist in the 3 directories
+    });
+
 
 ### series(tasks, [callback])
 
diff --git a/lib/async.js b/lib/async.js
index 24e6279..a20211e 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -396,6 +396,18 @@
         };
     };
 
+    async.concat = function(arr, fn, callback){
+        var r = [];
+        async.forEach(arr, function(x, cb){
+            fn(x, function(err, y){
+                r = r.concat(y || []);
+                cb(err);
+            });
+        }, function(err){
+            callback(err, r);
+        });
+    };
+
     var _console_fn = function(name){
         return function(fn){
             var args = Array.prototype.slice.call(arguments, 1);
diff --git a/test/test-async.js b/test/test-async.js
index de03d88..4175145 100644
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -872,3 +872,31 @@ exports['noConflict'] = function(test){
         test.done();
     });
 };
+
+exports['concat'] = function(test){
+    var iterator = function (x, cb) {
+        var r = [];
+        while (x > 0) {
+            r.push(x);
+            x--;
+        }
+        process.nextTick(function(){
+            cb(null, r);
+        });
+    };
+    async.concat([1,2,3], iterator, function(err, results){
+        test.same(results, [1,2,1,3,2,1]);
+        test.ok(!err);
+        test.done();
+    });
+};
+
+exports['concat error'] = function(test){
+    var iterator = function (x, cb) {
+        cb(new Error('test error'));
+    };
+    async.concat([1,2,3], iterator, function(err, results){
+        test.ok(err);
+        test.done();
+    });
+};

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/pkg-javascript/node-async.git