NoHandlerRegisteredError

The Cause

You attempted to emit an action, but no handler is registered for that action name. Actions require at least one handler to be registered when running in strict mode.

This error occurs when:

• You misspelled the action name
• The handler registration happens after the action is emitted
• The plugin that provides the handler hasn’t been loaded
• You’re using an action name that doesn’t exist

The Solution

To fix this:

1. Verify the action name: Check for typos in the action name

2. Ensure handlers are registered before use:

// ❌ Wrong order
await emitter.emitAction('my.action', params);
emitter.onAction('my.action', handler); // Too late!

// ✅ Correct order
emitter.onAction('my.action', handler);
await emitter.emitAction('my.action', params);

3. Check plugin loading: If the action is provided by a plugin, ensure the plugin is loaded in your configuration

4. Use the correct action name: Refer to the documentation for the correct action names

5. Using the non-strict mode: You can disable strict mode to allow actions to be emitted without handlers:

await emitter.emitAction('my.action', params, {
  strict: false,
});

Available core actions can be found in the Thymian documentation. If you’re developing a plugin, make sure to register your action handlers during plugin initialization.