Function wrapUserProvidedKey

docs/lib/react.js:17600–17602

* Wrap a `key` value explicitly provided by the user to distinguish it from * implicitly-generated keys generated by a component's index in its parent. * * @param {string} key Value of a user-provided `key` attribute * @return {string}

(key)

 * @return {string}
 */
function wrapUserProvidedKey(key) {
  return '$' + escapeUserProvidedKey(key);
}

/**
 * @param {?*} children Children tree container.