node_modules/jszip/node_modules/core-js/library/modules/_is-array-iter.js

// check on default Array iterator
var Iterators  = require('./_iterators')
  , ITERATOR   = require('./_wks')('iterator')
  , ArrayProto = Array.prototype;

module.exports = function(it){
  return it !== undefined && (Iterators.Array === it || ArrayProto[ITERATOR] === it);
};