Function reconcileChildrenIterator

docs/external/js/react-dom.development.js:14096–14276

(returnFiber, currentFirstChild, newChildrenIterable, expirationTime)

    }

    function reconcileChildrenIterator(returnFiber, currentFirstChild, newChildrenIterable, expirationTime) {
      // This is the same implementation as reconcileChildrenArray(),
      // but using the iterator instead.
      var iteratorFn = getIteratorFn(newChildrenIterable);

      if (!(typeof iteratorFn === 'function')) {
        {
          throw Error( "An object is not an iterable. This error is likely caused by a bug in React. Please file an issue." );
        }
      }

      {
        // We don't support rendering Generators because it's a mutation.
        // See https://github.com/facebook/react/issues/12995
        if (typeof Symbol === 'function' && // $FlowFixMe Flow doesn't know about toStringTag
        newChildrenIterable[Symbol.toStringTag] === 'Generator') {
          if (!didWarnAboutGenerators) {
            error('Using Generators as children is unsupported and will likely yield ' + 'unexpected results because enumerating a generator mutates it. ' + 'You may convert it to an array with `Array.from()` or the ' + '`[...spread]` operator before rendering. Keep in mind ' + 'you might need to polyfill these features for older browsers.');
          }

          didWarnAboutGenerators = true;
        } // Warn about using Maps as children


        if (newChildrenIterable.entries === iteratorFn) {
          if (!didWarnAboutMaps) {
            error('Using Maps as children is unsupported and will likely yield ' + 'unexpected results. Convert it to a sequence/iterable of keyed ' + 'ReactElements instead.');
          }

          didWarnAboutMaps = true;
        } // First, validate keys.
        // We'll get a different iterator later for the main pass.


        var _newChildren = iteratorFn.call(newChildrenIterable);

        if (_newChildren) {
          var knownKeys = null;

          var _step = _newChildren.next();

          for (; !_step.done; _step = _newChildren.next()) {
            var child = _step.value;
            knownKeys = warnOnInvalidKey(child, knownKeys);
          }
        }
      }

      var newChildren = iteratorFn.call(newChildrenIterable);

      if (!(newChildren != null)) {
        {
          throw Error( "An iterable object provided no iterator." );
        }
      }

      var resultingFirstChild = null;
      var previousNewFiber = null;