hd-utils/lib/utils/validation/isIndex.js

A handy utils for modern JS developers

import isNumber from './isNumber';
/** Used as references for various `Number` constants. */
const MAX_SAFE_INTEGER = 9007199254740991;
/** Used to detect unsigned integer values. */
const reIsUint = /^(?:0|[1-9]\d*)$/;
/**
 * @description Checks if `value` is a valid array-like index.
 *
 * @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`.
 */
export default function isIndex(value, length) {
    value = Number(value);
    if (!isNumber(value))
        return false;
    const type = typeof value;
    length = length == null ? MAX_SAFE_INTEGER : length;
    return (!!length &&
        (type === 'number' ||
            (type !== 'symbol' && reIsUint.test(value?.toString()))) &&
        value > -1 &&
        value % 1 == 0 &&
        value < length);
}