Function getElementKey

packages/react/src/ReactChildren.js:72–84

* Generate a key string that identifies a element within a set. * * @param {*} element A element that could contain a manual key. * @param {number} index Index that is used if a manual key is not provided. * @return {string}

(element: any, index: number)

 * @return {string}
 */
function getElementKey(element: any, index: number): string {
  // Do some typechecking here since we call this blindly. We want to ensure
  // that we don't block potential future ES APIs.
  if (typeof element === 'object' && element !== null && element.key != null) {
    // Explicit key
    if (__DEV__) {
      checkKeyStringCoercion(element.key);
    }
    return escape('' + element.key);
  }
  // Implicit key determined by the index in the set
  return index.toString(36);
}

function resolveThenable<T>(thenable: Thenable<T>): T {
  switch (thenable.status) {