phaser/v3/src/tween/GetEaseFunction.js

var EaseMap = require('../math/easing/EaseMap');

var GetEaseFunction = function (ease, easeParams)
{
    if (typeof ease === 'string' && EaseMap.hasOwnProperty(ease))
    {
        if (easeParams)
        {
            var cloneParams = easeParams.slice(0);

            cloneParams.unshift(0);

            return function (v)
            {
                cloneParams[0] = v;

                return EaseMap[ease].apply(this, cloneParams);
            };
        }
        else
        {
            //  String based look-up
            return EaseMap[ease];
        }
    }
    else if (typeof ease === 'function')
    {
        //  Custom function
        return ease;
    }
    else if (Array.isArray(ease) && ease.length === 4)
    {
        //  Bezier function (TODO)
    }

    return EaseMap.Power0;
};

module.exports = GetEaseFunction;