facebook/react · error · Error

151

151

Error message

An iterable object provided no iterator.

What it means

Error "An iterable object provided no iterator." thrown in facebook/react.

Source

Thrown at packages/react-reconciler/src/ReactChildFiber.js:1474

          // $FlowFixMe[method-unbinding]
          Object.prototype.toString.call(newChildren) ===
            '[object AsyncGenerator]';
        if (!isGeneratorComponent) {
          if (!didWarnAboutGenerators) {
            console.error(
              'Using AsyncIterators as children is unsupported and will likely yield ' +
                'unexpected results because enumerating a generator mutates it. ' +
                'You can use an AsyncIterable that can iterate multiple times over ' +
                'the same items.',
            );
          }
          didWarnAboutGenerators = true;
        }
      }
    }

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

    // To save bytes, we reuse the logic by creating a synchronous Iterable and
    // reusing that code path.
    const iterator: Iterator<mixed> = {
      next(): IteratorResult<mixed, void> {
        return unwrapThenable(newChildren.next());
      },
    } as any;

    return reconcileChildrenIterator(
      returnFiber,
      currentFirstChild,
      iterator,
      lanes,
    );
  }

View on GitHub (pinned to eafeac097b)

When it happens

Trigger: Thrown at packages/react-reconciler/src/ReactChildFiber.js:1474 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/8816345ca30213e2. Report an issue: GitHub.