Function getEventKey

docs/external/js/react-dom.development.js:10020–10048

* @param {object} nativeEvent Native browser event. * @return {string} Normalized `key` property.

(nativeEvent)

   */

  function getEventKey(nativeEvent) {
    if (nativeEvent.key) {
      // Normalize inconsistent values reported by browsers due to
      // implementations of a working draft specification.
      // FireFox implements `key` but returns `MozPrintableKey` for all
      // printable characters (normalized to `Unidentified`), ignore it.
      var key = normalizeKey[nativeEvent.key] || nativeEvent.key;

      if (key !== 'Unidentified') {
        return key;
      }
    } // Browser does not implement `key`, polyfill as much of it as we can.


    if (nativeEvent.type === 'keypress') {
      var charCode = getEventCharCode(nativeEvent); // The enter-key is technically both printable and non-printable and can
      // thus be captured by `keypress`, no other non-printable key should.

      return charCode === 13 ? 'Enter' : String.fromCharCode(charCode);
    }

    if (nativeEvent.type === 'keydown' || nativeEvent.type === 'keyup') {
      // While user keyboard layout determines the actual meaning of each
      // `keyCode` value, almost all function keys have a universal value.
      return translateToKey[nativeEvent.keyCode] || 'Unidentified';
    }

    return '';
  }

  /**
   * @interface KeyboardEvent