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