@unknovvn/eventmediatr NPM

EventMediatr is minimal implementation of MediatR pattern based on eventEmitter

Install

$ npm install @unknovvn/eventmediatr

Usage

Publish

Should be used when request object has a constructor

const eventMediatr = new EventMediatr();

class ExampleRequest {
  example;

  constructor(example) {
    this.example = example;
  }
}

class ClassAsyncHandler {
  handle = async (request) => {
    console.log(
      "ClassAsyncHandler handle starting with request = " +
        JSON.stringify(request)
    );

    return await new Promise((resolve) => {
      console.log("ClassAsyncHandler handle finished");
      resolve(request.example);
    });
  };
}

eventMediatr.registerHandler("ExampleRequest", new ClassAsyncHandler());
eventMediatr
  .publish(new ExampleRequest("Example value"))
  .then((result) => console.log("ClassAsyncHandler result = " + result));

PublishByName

Should be used when request object doesn't have constructor

export default class AsyncHandler {
  constructor() {}

  handle = async () => {
    console.log("Async handle starting");
    return await new Promise((resolve) => {
      setTimeout(() => {
        console.log("Async handle finished");
        resolve();
      }, 2000);
    });
  };
}

export default class SyncHandler {
  constructor() {}

  handle = () => {
    console.log("Async handle starting");
    return setTimeout(() => {
      console.log("Sync handle finished");
    }, 2000);
  };
}

const eventMediatr = new EventMediatr();

eventMediatr.registerHandler("async", new AsyncHandler());
eventMediatr.publishByName("async", {});

eventMediatr.registerSyncHandler("sync", new SyncHandler());
eventMediatr.publishByName("sync", {});

eventMediatr.publish("async", {});
eventMediatr.publish("sync", {});