facebook/react · error · Error

231

231

Error message

Expected `${registrationName}` listener to be a function, instead got a value of `${typeof listener}` type.

What it means

Error "Expected `${registrationName}` listener to be a function, instead got a value of `${typeof listener}` type." thrown in facebook/react.

Source

Thrown at packages/react-native-renderer/src/legacy-events/ResponderEventPlugin.js:255

    fn(path[i], 'bubbled', arg);
  }
}

function getListener(inst, registrationName) {
  const stateNode = inst.stateNode;
  if (stateNode === null) {
    // Work in progress (ex: onload events in incremental mode).
    return null;
  }
  const props = getFiberCurrentPropsFromNode(stateNode);
  if (props === null) {
    // Work in progress.
    return null;
  }
  const listener = props[registrationName];

  if (listener && typeof listener !== 'function') {
    throw new Error(
      `Expected \`${registrationName}\` listener to be a function, instead got a value of \`${typeof listener}\` type.`,
    );
  }

  return listener;
}

function listenerAtPhase(inst, event, propagationPhase: PropagationPhases) {
  const registrationName =
    event.dispatchConfig.phasedRegistrationNames[propagationPhase];
  return getListener(inst, registrationName);
}

function accumulateDirectionalDispatches(inst, phase, event) {
  if (__DEV__) {
    if (!inst) {
      console.error('Dispatching inst must not be null');
    }

View on GitHub (pinned to eafeac097b)

When it happens

Trigger: Thrown at packages/react-native-renderer/src/legacy-events/ResponderEventPlugin.js:255 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/035072e405749161. Report an issue: GitHub.