Type Alias Events

Type declaration

• emit: (<EventName>(event: JimpexEventName, payload: JimpexEventPayload<EventName>) => void)

  Emits an event and call all its listeners.

  Example

  // Extend the interface to type the payload.
    interface JimpexEvents {
      myEvent: { message: string };
    }
    // Add the listener.
    events.on('myEvent', ({ message }) => {
      console.log('Event received:', message);
    });
    // Trigger the event.
    events.emit('myEvent', { message: 'Hello' });
    // prints "Event received: Hello"
  Copy

  • • <EventName>(event, payload): void

    • Type Parameters

      • EventName extends JimpexEventName

        The literal type of the event, to generate the type of the payload.

      Parameters

      • event: JimpexEventName

        The name of the events.
      • payload: JimpexEventPayload<EventName>

        Context information for the event.

      Returns void

• on: (<EventName>(eventName: EventName, listener: JimpexEventListener<EventName>) => (() => boolean))

  Adds a new event listener.

  Example

  const unsubscribe = events.on('afterStart', ({ app }) => {
      app.getLogger().info('Hello world!');
      unsubscribe();
    });
  Copy

  • • <EventName>(eventName, listener): (() => boolean)

    • Type Parameters

      • EventName extends JimpexEventNameLike

        The literal type of the event, to generate the type of the listener.

      Parameters

      • eventName: EventName
      • listener: JimpexEventListener<EventName>

        The listener function.

      Returns (() => boolean)

      An unsubscribe function to remove the listener.

      • • (): boolean

        • Returns boolean

• once: (<EventName>(eventName: EventName, listener: JimpexEventListener<EventName>) => (() => boolean))

  Adds an event listener that will only be executed once.

  Example

  events.once('afterStart', ({ app }) => {
      app.getLogger().info('Hello world!');
      unsubscribe();
    });
  Copy

  • • <EventName>(eventName, listener): (() => boolean)

    • Type Parameters

      • EventName extends JimpexEventNameLike

        The literal type of the event, to generate the type of the listener.

      Parameters

      • eventName: EventName
      • listener: JimpexEventListener<EventName>

        The listener function.

      Returns (() => boolean)

      An unsubscribe function to remove the listener.

      • • (): boolean

        • Returns boolean

• reduce: (<EventName>(event: JimpexReducerEventName, target: JimpexReducerEventTarget<EventName>, payload: JimpexReducerEventPayload<EventName>) => Promise<JimpexReducerEventTarget<EventName>>)

  Asynchronously reduces a target using an event. It's like emit, but the event listeners return a modified (or not) version of the target.

  Example

  // Extend the interface to type the target.
    interface JimpexReducerEventTargets {
      myReducer: unknown[];
    }
    // Extend the interface to type the payload.
    interface JimpexReducerEventPayloads {
      myReducer: {
        message: string;
      };
    }
    // Add the reducer.
    events.on('myReducer', async (target, { message }) => {
      const data = await fetch('https://api.example.com/' + message);
      target.push(data);
      return target;
    });
    // Trigger the event.
    const result = await events.reduce('myReducer', [], { message: 'Hello' });
    // result would be a list of data fetched from the API.
  Copy

  • • <EventName>(event, target, payload): Promise<JimpexReducerEventTarget<EventName>>

    • Type Parameters

      • EventName extends JimpexReducerEventName

        The literal type of the event, to generate the types of the target and the payload.

      Parameters

      • event: JimpexReducerEventName

        The name of the event.
      • target: JimpexReducerEventTarget<EventName>

        The variable to reduce with the reducers/listeners.
      • payload: JimpexReducerEventPayload<EventName>

        Context information for the event.

      Returns Promise<JimpexReducerEventTarget<EventName>>

      A version of the target processed by the listeners.

• reduceSync: (<EventName>(event: JimpexReducerEventName, target: JimpexReducerEventTarget<EventName>, payload: JimpexReducerEventPayload<EventName>) => JimpexReducerEventTarget<EventName>)

  Synchronously reduces a target using an event. It's like emit, but the events listener return a modified (or not) version of the target.

  Example

  // Extend the interface to type the target.
    interface JimpexReducerEventTargets {
      myReducer: string[];
    }
    // Extend the interface to type the payload.
    interface JimpexReducerEventPayloads {
      myReducer: {
        message: string;
      };
    }
    // Add the reducer.
    events.on('myReducer', (target, { message }) => {
      target.push(message);
      return target;
    });
    // Trigger the event.
    events.reduce('event', [], 'Hello');
    // returns ['Hello']
  Copy

  • • <EventName>(event, target, payload): JimpexReducerEventTarget<EventName>

    • Type Parameters

      • EventName extends JimpexReducerEventName

        The literal type of the event, to generate the types of the target and the payload.

      Parameters

      • event: JimpexReducerEventName

        The name of the event.
      • target: JimpexReducerEventTarget<EventName>

        The variable to reduce with the reducers/listeners.
      • payload: JimpexReducerEventPayload<EventName>

        Context information for the event.

      Returns JimpexReducerEventTarget<EventName>

      A version of the target processed by the listeners.