core-js/internals/to-index.js

'use strict';
var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
var toLength = require('../internals/to-length');

var $RangeError = RangeError;

// `ToIndex` abstract operation
// https://tc39.es/ecma262/#sec-toindex
module.exports = function (it) {
  if (it === undefined) return 0;
  var number = toIntegerOrInfinity(it);
  var length = toLength(number);
  if (number !== length) throw new $RangeError('Wrong length or index');
  return length;
};