added default concurrency for queue, closes #249

2 files changed, 56 insertions, 0 deletions

diff --git a/lib/async.js b/lib/async.js
index 3ebad60..5aac1b1 100755
--- a/lib/async.js
+++ b/lib/async.js
@@ -693,6 +693,9 @@
     };
 
     async.queue = function (worker, concurrency) {
+        if (concurrency === undefined) {
+            concurrency = 1;
+        }
         function _insert(q, data, pos, callback) {
           if(data.constructor !== Array) {
               data = [data];
diff --git a/test/test-async.js b/test/test-async.js
index e9efdd3..ddc86fe 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -1689,6 +1689,59 @@ exports['queue'] = function (test) {
     };
 };
 
+exports['queue default concurrency'] = function (test) {
+    var call_order = [],
+        delays = [160,80,240,80];
+
+    // order of completion: 1,2,3,4
+
+    var q = async.queue(function (task, callback) {
+        setTimeout(function () {
+            call_order.push('process ' + task);
+            callback('error', 'arg');
+        }, delays.splice(0,1)[0]);
+    });
+
+    q.push(1, function (err, arg) {
+        test.equal(err, 'error');
+        test.equal(arg, 'arg');
+        test.equal(q.length(), 3);
+        call_order.push('callback ' + 1);
+    });
+    q.push(2, function (err, arg) {
+        test.equal(err, 'error');
+        test.equal(arg, 'arg');
+        test.equal(q.length(), 2);
+        call_order.push('callback ' + 2);
+    });
+    q.push(3, function (err, arg) {
+        test.equal(err, 'error');
+        test.equal(arg, 'arg');
+        test.equal(q.length(), 1);
+        call_order.push('callback ' + 3);
+    });
+    q.push(4, function (err, arg) {
+        test.equal(err, 'error');
+        test.equal(arg, 'arg');
+        test.equal(q.length(), 0);
+        call_order.push('callback ' + 4);
+    });
+    test.equal(q.length(), 4);
+    test.equal(q.concurrency, 1);
+
+    q.drain = function () {
+        test.same(call_order, [
+            'process 1', 'callback 1',
+            'process 2', 'callback 2',
+            'process 3', 'callback 3',
+            'process 4', 'callback 4'
+        ]);
+        test.equal(q.concurrency, 1);
+        test.equal(q.length(), 0);
+        test.done();
+    };
+};
+
 exports['queue error propagation'] = function(test){
     var results = [];