/**
 * 利用reduce方法实现map方法
 * @param {function} callback map回调函数
 * @param {object} context callback执行时的this上下文对象
 */
Array.prototype.mapImplementedByReduce = function (callback, context = null) {
    const reducer = function (accumulator, currentValue, index, array) {
        const result = callback.call(context, currentValue, index, array);
        accumulator.push(result);
        return accumulator;
    }
    return this.reduce(reducer, []);
}

/**
 * test
 */
const arr = [1, 3, 5];
const callback = function (number, index, array) {
    return Math.pow(number, 3);
}

console.log(arr.mapImplementedByReduce(callback)); // [ 1, 27, 125 ]