phaser/src/utils/object/GetValue.js

A fast, free and fun HTML5 Game Framework for Desktop and Mobile web browsers.

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */

//  Source object
//  The key as a string, or an array of keys, i.e. 'banner', or 'banner.hideBanner'
//  The default value to use if the key doesn't exist

/**
 * Retrieves a value from an object.
 *
 * @function Phaser.Utils.Objects.GetValue
 * @since 3.0.0
 *
 * @param {object} source - The object to retrieve the value from.
 * @param {string} key - The name of the property to retrieve from the object. If a property is nested, the names of its preceding properties should be separated by a dot (`.`) - `banner.hideBanner` would return the value of the `hideBanner` property from the object stored in the `banner` property of the `source` object.
 * @param {*} defaultValue - The value to return if the `key` isn't found in the `source` object.
 *
 * @return {*} The value of the requested key.
 */
var GetValue = function (source, key, defaultValue)
{
    if (!source || typeof source === 'number')
    {
        return defaultValue;
    }
    else if (source.hasOwnProperty(key))
    {
        return source[key];
    }
    else if (key.indexOf('.') !== -1)
    {
        var keys = key.split('.');
        var parent = source;
        var value = defaultValue;

        //  Use for loop here so we can break early
        for (var i = 0; i < keys.length; i++)
        {
            if (parent.hasOwnProperty(keys[i]))
            {
                //  Yes it has a key property, let's carry on down
                value = parent[keys[i]];

                parent = parent[keys[i]];
            }
            else
            {
                //  Can't go any further, so reset to default
                value = defaultValue;
                break;
            }
        }

        return value;
    }
    else
    {
        return defaultValue;
    }
};

module.exports = GetValue;