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js-queue Is Great for any queue

socket message queuing
async operations
synchronous operations
atomic operations
code with requirements before executing
queues you want to start running any time you add new items
any simple or complex queue operations
base class to extend
anything else that needs a queue
Anything which needs a stack instead of a queue.

Stable and easy to use

Works great in node.js, webpack, browserify, or any other commonjs loader or compiler. To use in plain old vanilla browser javascript without common js just replace the requires in the examples with script tags. We show that below too.

js-queue also exposes the easy-stack stack via require('js-queue/stack.js') this file exposes an ES6 stack which allows for Last In First Out (LIFO) queuing. This can come in handy depending on your application needs, check out the easy-stack javascript documentation it follows the js-queue interface but is node 6 or greater as it uses ES6 classes.

npm install js-queue

npm info : See npm trends and stats for js-queue

GitHub info :

Package details websites :

GitHub.io site. A prettier version of this site.
NPM Module. The npm page for the js-queue module.

This work is licenced via the DBAD Public Licence.

Exposed methods and values

key	type	paramaters	default	description
add	function	any number of functions		adds all parameter functions to queue and starts execution if autoRun is true, queue is not already running and queue is not forcibly stopped
next	function			executes next item in queue if queue is not forcibly stopped
clear	function			removes remaining items in the queue
contents	Array			Queue instance contents
autoRun	Bool		true	should autoRun queue when new item added
stop	Bool		false	setting this to true will forcibly prevent the queue from executing

Basic queue use in node, react, browserify, webpack or any other commonjs implementation


    var Queue=require('js-queue');
    //create a new queue instance
    var queue=new Queue;

    for(var i=0; i<50; i++){
        //add a bunch of stuff to the queue
        queue.add(makeRequest);
    }

    function makeRequest(){
        //do stuff
        console.log('making some request');

        this.next();
    }

Basic browser use

The only difference is including via a script tag instead of using require.


    <html>
            <head>
                    <!-- this is the only difference -->
                    <script src='./queue-vanilla.js'></script>
                    <script>
                            console.log('my awesome app script');
                            var queue=new Queue;

                            for(var i=0; i<50; i++){
                                queue.add(makeRequest);
                            }

                            function makeRequest(){
                                console.log('making some request');

                                this.next();
                            }
                    </script>
            </head>
            <body>
            </body>
    </html>

Basic use with websockets in node, react, browserify, webpack or any other commonjs implementation

This allows you to start adding requests immediately and only execute if the websocket is connected. To use in plain browser based JS without webpack or browserify just replace the requires with the script tag.


    var Queue=require('js-queue');

    //ws-share just makes it easier to share websocket code and ensure you don't open a websocket more than once
    var WS=require('ws-share');

    //js-message makes it easy to create and parse normalized JSON messages.
    var Message=require('js-message');

    //create a new queue instance
    var queue=new Queue;

    //force stop until websocket opened
    queue.stop=true;

    var ws=null;

    function startWS(){
        //websocket.org rocks
        ws=new WS('wss://echo.websocket.org/?encoding=text');

        ws.on(
            'open',
            function(){
                ws.on(
                    'message',
                    handleResponse
                );

                //now that websocket is opened allow auto execution
                queue.stop=false;
                queue.next();
            }
        );

        ws.on(
            'error',
            function(err){
                //stop execution of queue if there is an error because the websocket is likely closed
                queue.stop=true;
                //remove remaining items in the queue
                queue.clear();
                throw(err);
            }
        );

        ws.on(
            'close',
            function(){
                //stop execution of queue when the websocket closed
                queue.stop=true;
            }
        );
    }

    //simulate a lot of requests being queued up for the websocket
    for(var i=0; i<50; i++){
        queue.add(makeRequest);
    }

    var messageID=0;

    function handleResponse(e){
        var message=new Message;
        message.load(e.data);

        console.log(message.type,message.data);
    }

    function makeRequest(){
        messageID++;
        var message=new Message;
        message.type='testMessage';
        message.data=messageID;

        ws.send(message.JSON);

        this.next();
    }

    startWS();

Extending Queue


    var Queue=require('js-queue');

    //MyAwesomeQueue inherits from Queue
    MyAwesomeQueue.prototype = new Queue;
    //Constructor will extend Queue
    MyAwesomeQueue.prototype.constructor = MyAwesomeQueue;

    function MyAwesomeQueue(){
        //extend with some stuff your app needs,
        //maybe npm publish your extention with js-queue as a dependancy?
        Object.defineProperties(
            this,
            {
                isStopped:{
                    enumerable:true,
                    get:checkStopped,
                    set:checkStopped
                },
                removeThirdItem:{
                    enumerable:true,
                    writable:false,
                    value:removeThird
                }
            }
        );

        //enforce Object.assign for extending by locking down Class structure
        //no willy nilly cowboy coding
        Object.seal(this);

        function checkStopped(){
            return this.stop;
        }

        function removeThird(){
            //get the queue content
            var list=this.contents;
            //modify the queue content
            list.splice(2,1);
            //save the modified queue content
            this.contents=list;

            return this.contents;
        }
    }

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