/** * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer) * of an array-like value. */ var MAX_SAFE_INTEGER = Math.pow(2, 53) - 1; /** * Checks if `value` is a valid array-like index. * * @private * @param {*} value The value to check. * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index. * @returns {boolean} Returns `true` if `value` is a valid index, else `false`. */ function isIndex(value, length) { value = +value; length = length == null ? MAX_SAFE_INTEGER : length; return value > -1 && value % 1 == 0 && value < length; } module.exports = isIndex;