mirror of https://github.com/thangisme/notes.git
23 lines
707 B
JavaScript
23 lines
707 B
JavaScript
/** Used as references for various `Number` constants. */
|
|
var MAX_SAFE_INTEGER = 9007199254740991;
|
|
|
|
/** Used to detect unsigned integer values. */
|
|
var reIsUint = /^(?:0|[1-9]\d*)$/;
|
|
|
|
/**
|
|
* 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) {
|
|
length = length == null ? MAX_SAFE_INTEGER : length;
|
|
return !!length &&
|
|
(typeof value == 'number' || reIsUint.test(value)) &&
|
|
(value > -1 && value % 1 == 0 && value < length);
|
|
}
|
|
|
|
module.exports = isIndex;
|