JavaScript multithreaded Asynchronous queue

First of all, you need to know the general usage of jquery.deferred, then, let's get to the point:

Library code:

/*! * Multithreaded Asynchronous Queue * relies on jQuery 1.8+ (if you're using 1.6 or 1.7, just replace the then method in the source with the pipe method)*//** * @n {number} positive integer, thread count*/functionQueue (n) {n= parseint (n | | 1, 10); return(n && n > 0)?NewQueue.prototype.init (n):NULL;} Queue.prototype={init:function(n) { This. threads = [];  This. taskList = [];  while(n--) {             This. Threads.push (New  This. Thread)}},/** * @callback {fucntion} Promise object is done when the callback function, its return value must be a Promise object*/Push:function(callback) {if(typeofCallback!== ' function ')return; varindex = This. Indexofidle (); if(Index! =-1) {             This. Threads[index].idle (callback)Try{console.log (' thread-' + (index+1) + ' accept the task! ')}Catch(e) {}}Else {             This. Tasklist.push (callback);  for(vari = 0, L = This. threads.length; I < L; i++) {                (function(thread, self, id) {Thread.idle (function(){                        if(Self.taskList.length > 0) {                            Try{console.log (' thread-' + (id+1) + ' accept the task! ')}Catch(e) {}varPromise = Self.taskList.pop () ();//the correct return value should be a Promise object                            returnPromise.promise?promise:thread.promise; } Else {                            returnthread.promise})}) ( This. Threads[i], This, i); }}, Indexofidle:function () {        varThreads = This. threads, Thread=NULL, Index=-1;  for(vari = 0, L = threads.length; I < L; i++) {Thread=Threads[i]; if(thread.promise.state () = = = ' Resolved ') {Index=i;  Break; }        }        returnindex; }, Thread:function () {         This. Promise = $.        Deferred (). Resolve (). Promise ();  This. Idle =function(callback) { This. Promise = This. Promise.then (Callback)}}; Queue.prototype.init.prototype= Queue.prototype;

Examples of Use:

    varQueue =NewQueue (3); Create a queue with 3 threads
Task-1 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},8000); returndefer.promise ()})
Task-2 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},2000); returndefer.promise ()})
Task-3 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},6000); returndefer.promise ()})
Task-4 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},3000); returndefer.promise ()})
Task-5 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},2000); returndefer.promise ()})
Task-6 Queue.push (function(){        vardefer = $.        Deferred (); SetTimeout (function() {defer.resolve ()},2000); returndefer.promise ()})

The console has a function (called a task) that shows Queue.push, which process is ultimately processed

After instantiation, all 3 threads in the queue are in an idle state.
assigning task-1 to Thread 1, this task takes 8s
assigning task-2 to Thread 2, this task takes 2s
assigning task-3 to Thread 3, this task takes 6s

Because there are currently no idle processes, the internal queue adds task-4, task-5, task-6 to the waiting area

Because task-2 takes 2s, process 2 is first liberated, then TASK-4 is assigned to process 2, and so on, the last console shows the process usage is: 1, 2, 3, 2, 2, 3

JavaScript multithreaded Asynchronous queue