• wm-countdown.js

angular.module('wm.countdown', []).service('Countdown', ['$interval', function($interval) {

    /**
     * The Countdown Object
     * @param {Number} initialValue An initial value for countdown
     * @param {Number=1000} milliseconds The interval for countdown in milliseconds
     */
    function Countdown(initialValue, milliseconds) {

        if (! angular.isNumber(initialValue)) {
            throw Error("argument 'initialValue' #1 of Countdown excepts type Number");
        }

        if (! angular.isNumber(milliseconds)) {
            throw Error("argument 'milliseconds' #2 of Countdown excepts type Number");
        }


        this.$$initialValue = initialValue;

        this.$$currentValue = initialValue;

        this.$$milliseconds = milliseconds || 1000;

        this.$$interval = null;

        this.$$state = 'initialized';
    };

    /**
     * Start the countdown
     * 
     * @return {Countdown}
     */
    Countdown.prototype.start = function() {

        var that = this;

        if (that.isPending()) return;

        that.$$state = 'pending';

        that.$$interval = $interval(function() {

            that.$$currentValue -= 1;

            if (that.$$currentValue === 0) {
                that.cancel();
                that.$$state = 'completed';
            }

        }, that.$$milliseconds);

        return this;
    };

    /**
     * Check if "pause" method was called
     *     
     * @return {Boolean}
     */
    Countdown.prototype.isPaused = function() {
        return this.$$state === 'paused';
    };

    /**
     * Check if "start" method was called
     *     
     * @return {Boolean}
     */
    Countdown.prototype.isStarted = function() {
        return this.$$state !== 'initialized';
    };

    /**
     * Checks if interval is running
     *     
     * @return {Boolean}
     */
    Countdown.prototype.isPending = function() {
        return this.$$state === 'pending';
    };

    /**
     * Check if "cancel" method was called
     *     
     * @return {Boolean}
     */
    Countdown.prototype.isCanceled = function() {
        return this.$$state === 'canceled';
    };

    /**
     * Pause the interval. The countdown is frozen at the current position
     * 
     * @return {Countdown}
     */
    Countdown.prototype.pause = function() {

        $interval.cancel(this.$$interval);

        this.$$interval = null;

        this.$$state = 'paused';

        return this;
    };

    /**
     * Cancel the interval. The countdown is set to initial value
     * 
     * @return {Countdown}
     */
    Countdown.prototype.cancel = function() {

        this.pause();

        this.$$currentValue = this.$$initialValue;

        this.$$state = 'canceled';

        return this;
    };

    /**
     * Gets the current value of Countdown
     * 
     * @return {Number}
     */
    Countdown.prototype.currentValue = function() {
        return this.$$currentValue;
    };


    return Countdown;

}]);