barracks

Barracks

Event dispatcher for the flux architecture. Provides event composition through this.waitFor() and checks for circular dependencies with a small interface of only 3 functions.

Installation

$ npm i --save barracks

Overview

/**
 * Initialize a dispatcher.
 */

var barracks = require('barracks');
var dispatcher = barracks({
  users: {
    add: function(user, done) {
      console.log(user + ' got added');
      done();
    },
    remove: function(user, done) {
      console.log(user + ' was removed');
      done();
    }
  },
  courses: {
    get: function(val, done) {
      console.log('Get ' + val);
      done();
    },
    set: function(val, done) {
      console.log('Set ' + val);
      done();
    }
  }
});

/**
 * Dispatch an event.
 */

dispatcher('users_add', 'Loki');
// => 'Loki got added'

API

dispatcher = barracks(actions)

Initialize a new barracks instance. The actions object should contain functions, namespaced at most one level deep. Returns a function.

// Initialize without namespaces.
var dispatcher = barracks({
  user: function() {},
  group: function() {}
});

// Initialize with namespaces.
var dispatcher = barracks({
  users: {
    add: function() {},
    remove: function() {}
  },
  courses: {
    get: function() {},
    put: function() {}
  }
});

dispatcher(action, data)

barracks() returns a dispatcher function which can be called to dispatch an action. By dispatching an action you call the corresponding function from the dispatcher and pass it the data. You can think of it as just calling a function.

In order to access namespaced functions you can delimit your string with underscores. So to access courses.get you'd dispatch the string courses_get.

// Call a non-namespaced action.
dispatcher('group', [123, 'hello']);

// Call a namespaced action.
dispatcher('users_add', {foo: 'bar'});

ctx.waitFor(action)

Execute another function within the dispatcher before proceeding. Registered callbacks are always bound to the scope of the dispatcher, so you can just call this.waitFor to access the function from within a registered callback.

In the example below users_initalize will delegate execution to user_add and user_listen before proceeding to execute its own code.

var socket = require('sockjs-client');
var request = require('request');

var dispatcher = barracks({
  users: {
    initialize: function(done) {
      var arr = ['user_add', 'user_listen'];
      this.waitFor(arr, function() {
        console.log('initialized');
        done();
      });
    },
    add: function(done) {
      request('myapi.co/api/users', function(err, res) {
        userStore.set(res);
        done();
      });
    },
    listen: function(done) {
      var sock = new socket('myapi.co/api/socket');
      sock.onMessage(console.log);
      done();
    }
  }
});

ctx.locals=

this.locals is shared between all (delegated) function calls and acts as the location to share data between function calls. For example when you retrieve a token from a store and want to make it available to all subsequent functions.

The payload provided by dispatcher() is available under this.locals.payload.

var request = require('request');

var dispatcher = barracks({
  users: {
    add: add,
    listen: listen
  }
});

function add(done) {
  request('myapi.co/api/auth', function(err, res) {
    this.locals.token = res.token;
    done();
  });
}

function listen(done) {
  this.waitFor(['user_add'], handleWaitfor);

  function handleWaitfor() {
    var url = 'myapi.co/me?token=' + this.locals.token;
    request(url, handleRequest);
  }

  function handleRequest(err, res) {
    console.log(res);
    done();
  }
}

dispatcher('user_listen');

License

MIT © Yoshua Wuyts