Function getEventKey

code/controlled-uncontrolled/public/app.js:4817–4844

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

(nativeEvent)

 * @return {string} Normalized `key` property.
 */
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