code: function validatePropertyKey(name, element, parentType) {
    if (!NUMERIC_PROPERTY_REGEX.test(name)) {
      return;
    }
    warnAndMonitorForKeyUse(
      'Child objects should have non-numeric keys so ordering is preserved.',
      element,
      parentType
    );
  }
docs: Warn if the key is being defined as an object property but has an incorrect
  value.
  
  @internal
  @param {string} name Property name of the key.
  @param {ReactElement} element Component that requires a key.
  @param {*} parentType element's parent's type.