added unit testing, and started implementing unit tests...phew

node_modules/async/priorityQueue.js

@@ -0,0 +1,98 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+
+exports.default = function (worker, concurrency) {
+    // Start with a normal queue
+    var q = (0, _queue2.default)(worker, concurrency);
+
+    // Override push to accept second parameter representing priority
+    q.push = function (data, priority, callback) {
+        if (callback == null) callback = _noop2.default;
+        if (typeof callback !== 'function') {
+            throw new Error('task callback must be a function');
+        }
+        q.started = true;
+        if (!(0, _isArray2.default)(data)) {
+            data = [data];
+        }
+        if (data.length === 0) {
+            // call drain immediately if there are no tasks
+            return (0, _setImmediate2.default)(function () {
+                q.drain();
+            });
+        }
+
+        priority = priority || 0;
+        var nextNode = q._tasks.head;
+        while (nextNode && priority >= nextNode.priority) {
+            nextNode = nextNode.next;
+        }
+
+        for (var i = 0, l = data.length; i < l; i++) {
+            var item = {
+                data: data[i],
+                priority: priority,
+                callback: callback
+            };
+
+            if (nextNode) {
+                q._tasks.insertBefore(nextNode, item);
+            } else {
+                q._tasks.push(item);
+            }
+        }
+        (0, _setImmediate2.default)(q.process);
+    };
+
+    // Remove unshift function
+    delete q.unshift;
+
+    return q;
+};
+
+var _isArray = require('lodash/isArray');
+
+var _isArray2 = _interopRequireDefault(_isArray);
+
+var _noop = require('lodash/noop');
+
+var _noop2 = _interopRequireDefault(_noop);
+
+var _setImmediate = require('./setImmediate');
+
+var _setImmediate2 = _interopRequireDefault(_setImmediate);
+
+var _queue = require('./queue');
+
+var _queue2 = _interopRequireDefault(_queue);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+module.exports = exports['default'];
+
+/**
+ * The same as [async.queue]{@link module:ControlFlow.queue} only tasks are assigned a priority and
+ * completed in ascending priority order.
+ *
+ * @name priorityQueue
+ * @static
+ * @memberOf module:ControlFlow
+ * @method
+ * @see [async.queue]{@link module:ControlFlow.queue}
+ * @category Control Flow
+ * @param {AsyncFunction} worker - An async function for processing a queued task.
+ * If you want to handle errors from an individual task, pass a callback to
+ * `q.push()`.
+ * Invoked with (task, callback).
+ * @param {number} concurrency - An `integer` for determining how many `worker`
+ * functions should be run in parallel.  If omitted, the concurrency defaults to
+ * `1`.  If the concurrency is `0`, an error is thrown.
+ * @returns {module:ControlFlow.QueueObject} A priorityQueue object to manage the tasks. There are two
+ * differences between `queue` and `priorityQueue` objects:
+ * * `push(task, priority, [callback])` - `priority` should be a number. If an
+ *   array of `tasks` is given, all tasks will be assigned the same priority.
+ * * The `unshift` method was removed.
+ */