isLength.js (802B)
1 /** Used as references for various `Number` constants. */ 2 var MAX_SAFE_INTEGER = 9007199254740991; 3 4 /** 5 * Checks if `value` is a valid array-like length. 6 * 7 * **Note:** This method is loosely based on 8 * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength). 9 * 10 * @static 11 * @memberOf _ 12 * @since 4.0.0 13 * @category Lang 14 * @param {*} value The value to check. 15 * @returns {boolean} Returns `true` if `value` is a valid length, else `false`. 16 * @example 17 * 18 * _.isLength(3); 19 * // => true 20 * 21 * _.isLength(Number.MIN_VALUE); 22 * // => false 23 * 24 * _.isLength(Infinity); 25 * // => false 26 * 27 * _.isLength('3'); 28 * // => false 29 */ 30 function isLength(value) { 31 return typeof value == 'number' && 32 value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER; 33 } 34 35 module.exports = isLength;