Event Bus for Meteor

Reactivity in all its glory, but sometimes you just need a plain old event bus.

Installation

meteor add lookback:eventbus

This package runs both on the server and client.

API

Create bus objects (preferrably globals) by calling the exported EventBus function:

Bus = EventBus();

Three methods are exposed along with many aliases, matching your preference:

dispatch

Aliases: add, send, emit, trigger

dispatch(event:String, [data...]);

Trigger an event and sends it off to the bus. Call with the event name and as many arguments with as many types as you want:

Bus.dispatch('MyEvent', 'Important info string', [1, 2], {foo: 'bar'});

register

Aliases: on

register(event:String, handler:Function);

Register a listener on the bus and handle it with a handler function. The data you sent (if any) in dispatch will be available as arguments to the handler.

Bus.register('MyEvent', function(str, arr, obj) {
    console.log(str);
    // => 'Important info string'
    console.log(arr);
    // => [1, 2]
    console.log(obj);
    // => {foo: 'bar'}
});

remove

Aliases: off, deregister

remove(event:String, [handler:Function]);

Stop listening to event completely, or remove a single handler only.

// Remove specialHandler only.
Bus.remove('MyEvent', specialHandler);

// Remove all listeners to 'MyEvent'.
Bus.remove('MyEvent');

Sample usage

// In some init file.
Bus = EventBus();

// Somewhere else. 
Meteor.methods({
  addPost: function(title, text) {
    check(title, String);
    check(text, String);

    var post = {
      title: title,
      text: text,
      author: Meteor.userId()
    };

    Posts.insert(post, function(err, postId) {
      if(!err) {
        // Add the post id and send off to bus!
        Bus.dispatch('posts/new', _.extend(post, {_id: postId}));
      }
    });
  }
});

// Somewhere completely else (in a notification-center.js file perhaps?)

Bus.register('posts/new', function(post) {
  check(post, {
    _id: String,
    title: String,
    text: String,
    author: String
  });

  // Send email to subscribers.
  var subscribers = Posts.getSubscribers(post._id);
  EmailNotifications.sendSubscriptionEmail(subscribers, post);

  // Perhaps some analytics tracking?
  Analytics.track('New Post', post._id);

  // In-app notifications?
  Notifications.newPost(post._id);

  // ..
});

Tests

Run tests with:

make test

Or check them out in browser on localhost:5000:

meteor test-packages --port 5000 --driver-package respondly:test-reporter ./

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Made by Lookback.