Function is

docs/external/js/react-dom.development.js:9672–9675

* inlined Object.is polyfill to avoid requiring consumers ship their own * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is

(x, y)

   * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
   */
  function is(x, y) {
    return x === y && (x !== 0 || 1 / x === 1 / y) || x !== x && y !== y // eslint-disable-line no-self-compare
    ;
  }

  var objectIs = typeof Object.is === 'function' ? Object.is : is;