phaser/src/utils/array/GetFirst.js

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2019 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

var SafeRange = require('./SafeRange');

/**
 * Returns the first element in the array.
 *
 * You can optionally specify a matching criteria using the `property` and `value` arguments.
 *
 * For example: `getAll('visible', true)` would return the first element that had its `visible` property set.
 *
 * Optionally you can specify a start and end index. For example if the array had 100 elements,
 * and you set `startIndex` to 0 and `endIndex` to 50, it would search only the first 50 elements.
 *
 * @function Phaser.Utils.Array.GetFirst
 * @since 3.4.0
 *
 * @param {array} array - The array to search.
 * @param {string} [property] - The property to test on each array element.
 * @param {*} [value] - The value to test the property against. Must pass a strict (`===`) comparison check.
 * @param {integer} [startIndex=0] - An optional start index to search from.
 * @param {integer} [endIndex=array.length] - An optional end index to search up to (but not included)
 *
 * @return {object} The first matching element from the array, or `null` if no element could be found in the range given.
 */
var GetFirst = function (array, property, value, startIndex, endIndex)
{
    if (startIndex === undefined) { startIndex = 0; }
    if (endIndex === undefined) { endIndex = array.length; }

    if (SafeRange(array, startIndex, endIndex))
    {
        for (var i = startIndex; i < endIndex; i++)
        {
            var child = array[i];

            if (!property ||
                (property && value === undefined && child.hasOwnProperty(property)) ||
                (property && value !== undefined && child[property] === value))
            {
                return child;
            }
        }
    }

    return null;
};

module.exports = GetFirst;