| Leo Repp | 58b9f11 | 2021-11-22 11:57:47 +0100 | [diff] [blame^] | 1 | /** Used as references for various `Number` constants. */ |
| 2 | var MAX_SAFE_INTEGER = 9007199254740991; |
| 3 | |
| 4 | /** Used to detect unsigned integer values. */ |
| 5 | var reIsUint = /^(?:0|[1-9]\d*)$/; |
| 6 | |
| 7 | /** |
| 8 | * Checks if `value` is a valid array-like index. |
| 9 | * |
| 10 | * @private |
| 11 | * @param {*} value The value to check. |
| 12 | * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index. |
| 13 | * @returns {boolean} Returns `true` if `value` is a valid index, else `false`. |
| 14 | */ |
| 15 | function isIndex(value, length) { |
| 16 | var type = typeof value; |
| 17 | length = length == null ? MAX_SAFE_INTEGER : length; |
| 18 | |
| 19 | return !!length && |
| 20 | (type == 'number' || |
| 21 | (type != 'symbol' && reIsUint.test(value))) && |
| 22 | (value > -1 && value % 1 == 0 && value < length); |
| 23 | } |
| 24 | |
| 25 | module.exports = isIndex; |