xpl/node_modules/core-js/library/modules/es6.string.iterator.js

'use strict';
var $at = require('./_string-at')(true);

// 21.1.3.27 String.prototype[@@iterator]()
require('./_iter-define')(String, 'String', function (iterated) {
  this._t = String(iterated); // target
  this._i = 0;                // next index
// 21.1.5.2.1 %StringIteratorPrototype%.next()
}, function () {
  var O = this._t;
  var index = this._i;
  var point;
  if (index >= O.length) return { value: undefined, done: true };
  point = $at(O, index);
  this._i += point.length;
  return { value: point, done: false };
});