# Yahoo! UI Library

### queue 3.0.0b1

Yahoo! UI Library > queue > queue-base.js (source view)
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    /**
     * <p>The Queue module adds a common data structure for FIFO operations. In its
     * simplest form, it is little more than an array wrapper. Additional
     * submodules introduce more functionality such as promotion and removal of
     * queued items.</p>
     *
     * <p>An AsyncQueue class is provided in the queue-run submodule.  This class
     * affords a mechanism to do complex sequential and iterative callback
     * execution across configured timeouts.
     *
     * @module queue
     */

    /**
     * A simple FIFO queue.  Items are added to the Queue with add(1..n items) and
     * removed using next().
     *
     * @module queue
     * @submodule queue-base
     * @class Queue
     * @param item* {MIXED} 0..n items to seed the queue
     */
    function Queue() {
        this._init();
        this.add.apply(this, arguments);
    }

    Queue.prototype = {
        /**
         * Initialize the queue
         *
         * @method _init
         * @protected
         */
        _init : function () {
            /**
             * The collection of enqueued items
             *
             * @property _q
             * @type {Array}
             * @protected
             */
            this._q = [];
        },

        /**
         * Get the next item in the queue.
         *
         * @method next
         * @return {MIXED} the next item in the queue
         */
        next : function () {
            return this._q.shift();
        },

        /**
         * Add 0..n items to the end of the queue
         *
         * @method add
         * @param item* {MIXED} 0..n items
         */
        add : function () {
            Y.Array.each(Y.Array(arguments,0,true),function (fn) {
                this._q.push(fn);
            },this);

            return this;
        },

        /**
         * Returns the current number of queued items
         *
         * @method size
         * @return {Number}
         */
        size : function () {
            return this._q.length;
        }
    };

    Y.Queue = Queue;

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