~~~ /** * 截取數組長度 * @param arr 數組 * @param n1 開始數組元素 * @param n2 結束數組元素 默認為數組的長度 * @returns {Array} 返回截取的新數組 * * getArrayNum([0,1,2,3,4,5,6,7,8,9],5,9) * [5, 6, 7, 8, 9] * * getArrayNum([0,1,2,3,4,5,6,7,8,9],2) * [2, 3, 4, 5, 6, 7, 8, 9] * */ function getArrayNum(arr, n1, n2) { let arr1 = [], len = n2 || arr.length - 1; for (let i = n1; i <= len; i++) { arr1.push(arr[i]) } return arr1; } ~~~