facebook/react · error · Error

150

150

Error message

An object is not an iterable. This error is likely caused by a bug in React. Please file an issue.

What it means

Error "An object is not an iterable. This error is likely caused by a bug in React. Please file an issue." thrown in facebook/react.

Source

Thrown at packages/react-reconciler/src/ReactChildFiber.js:1383

      const numberOfForks = newIdx;
      pushTreeFork(returnFiber, numberOfForks);
    }
    return resultingFirstChild;
  }

  function reconcileChildrenIteratable(
    returnFiber: Fiber,
    currentFirstChild: Fiber | null,
    newChildrenIterable: Iterable<mixed>,
    lanes: Lanes,
  ): Fiber | null {
    // This is the same implementation as reconcileChildrenArray(),
    // but using the iterator instead.

    const iteratorFn = getIteratorFn(newChildrenIterable);

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

    const newChildren = iteratorFn.call(newChildrenIterable);

    if (__DEV__) {
      if (newChildren === newChildrenIterable) {
        // We don't support rendering Generators as props because it's a mutation.
        // See https://github.com/facebook/react/issues/12995
        // We do support generators if they were created by a GeneratorFunction component
        // as its direct child since we can recreate those by rerendering the component
        // as needed.
        const isGeneratorComponent =
          returnFiber.tag === FunctionComponent &&
          // $FlowFixMe[method-unbinding]
          Object.prototype.toString.call(returnFiber.type) ===

View on GitHub (pinned to eafeac097b)

When it happens

Trigger: Thrown at packages/react-reconciler/src/ReactChildFiber.js:1383 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of facebook/react@eafeac097b (2026-08-21). Data as JSON: /api/errors/1d89db944a97d99d. Report an issue: GitHub.