phaser/v3/src/tween/TweenBuilder.js

var GetValue = require('../utils/object/GetValue');
var GetAdvancedValue = require('../utils/object/GetAdvancedValue');
var Tween = require('./Tween');
var RESERVED = require('./ReservedProps');
var GetEaseFunction = require('./GetEaseFunction');

var GetTargets = function (config)
{
    var targets = GetValue(config, 'targets', null);

    if (typeof targets === 'function')
    {
        targets = targets.call();
    }

    if (!Array.isArray(targets))
    {
        targets = [ targets ];
    }

    return targets;
};

var GetProps = function (config)
{
    var key;
    var keys = [];

    //  First see if we have a props object

    if (config.hasOwnProperty('props'))
    {
        for (key in config.props)
        {
            keys.push({ key: key, value: config.props[key] });
        }
    }
    else
    {
        for (key in config)
        {
            if (RESERVED.indexOf(key) === -1)
            {
                keys.push({ key: key, value: config[key] });
            }
        }
    }

    return keys;
};

var GetValueOp = function (target, key, value)
{
    var valueCallback;

    if (typeof value === 'number')
    {
        // props: {
        //     x: 400,
        //     y: 300
        // }

        valueCallback = function ()
        {
            return value;
        };
    }
    else if (typeof value === 'string')
    {
        // props: {
        //     x: '+400',
        //     y: '-300',
        //     z: '*2',
        //     w: '/2'
        // }

        var op = value[0];
        var num = parseFloat(value.substr(1));

        switch (op)
        {
            case '+':
                valueCallback = function ()
                {
                    return target[key] + num;
                };
                break;

            case '-':
                valueCallback = function ()
                {
                    return target[key] - num;
                };
                break;

            case '*':
                valueCallback = function ()
                {
                    return target[key] * num;
                };
                break;

            case '/':
                valueCallback = function ()
                {
                    return target[key] / num;
                };
                break;

            default:
                valueCallback = function ()
                {
                    return parseFloat(value);
                };
        }
    }
    else if (typeof value === 'function')
    {
        //  Technically this could return a number, string or object
        // props: {
        //     x: function () { return Math.random() * 10 },
        //     y: someOtherCallback
        // }

        valueCallback = GetValueOp(target, key, value.call());
    }
    else if (value.hasOwnProperty('value'))
    {
        //  Value may still be a string, function or a number
        // props: {
        //     x: { value: 400, ... },
        //     y: { value: 300, ... }
        // }

        valueCallback = GetValueOp(target, key, value.value);
    }

    return valueCallback;
};

var TweenBuilder = function (manager, config)
{
    //  Create arrays of the Targets and the Properties
    var targets = GetTargets(config);
    var props = GetProps(config);
    var tweens = [];

    //  Default Tween values
    var ease = GetEaseFunction(GetValue(config, 'ease', 'Power0'));
    var duration = GetAdvancedValue(config, 'duration', 1000);
    var yoyo = GetValue(config, 'yoyo', false);
    var repeat = GetAdvancedValue(config, 'repeat', 0);
    var loop = GetValue(config, 'loop', false);
    var delay = GetAdvancedValue(config, 'delay', 0);

    // var onCompleteDelay = 0;
    // var elasticity = 0;

    for (var p = 0; p < props.length; p++)
    {
        //  Get Tween value + op
        var key = props[p].key;
        var value = props[p].value;

        var iEase = GetEaseFunction(GetValue(value, 'ease', ease));
        var iDuration = GetAdvancedValue(value, 'duration', duration);
        var iYoyo = GetValue(value, 'yoyo', yoyo);
        var iRepeat = GetAdvancedValue(value, 'repeat', repeat);
        var iLoop = GetValue(value, 'loop', loop);
        var iDelay = GetAdvancedValue(value, 'delay', delay);

        for (var t = 0; t < targets.length; t++)
        {
            var target = targets[t];
            var valueOp = GetValueOp(target, key, value);

            var tween = new Tween(manager, targets[t], key, valueOp);

            //  Set all the other properties ...
            tween.ease = iEase;
            tween.duration = iDuration;
            tween.yoyo = iYoyo;
            tween.repeat = iRepeat;
            tween.loop = iLoop;
            tween.delay = iDelay;

            tweens.push(tween);

            manager.queue(tween);
        }
    }

    return tweens;
};

module.exports = TweenBuilder;