t-comm/lib/validate/is-index.js

专业、稳定、纯粹的工具库

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var _typeof = require('@babel/runtime/helpers/typeof');

function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }

var _typeof__default = /*#__PURE__*/_interopDefaultLegacy(_typeof);

/**
 * Used as references for various `Number` constants.
 * @private
 */
var MAX_SAFE_INTEGER = 9007199254740991;
/**
 *  Used to detect unsigned integer values.
 * @private
 */
var reIsUint = /^(?:0|[1-9]\d*)$/;
/**
 * 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`.
 */
function isIndex(value, length) {
  if (length === void 0) {
    length = MAX_SAFE_INTEGER;
  }
  var type = _typeof__default["default"](value);
  return !!length && (type == 'number' || type != 'symbol' && reIsUint.test(value)) && value > -1 && value % 1 == 0 && value < length;
}

exports.isIndex = isIndex;