What is scaleApp?

scaleApp is a tiny JavaScript framework for scalable and maintainable One-Page-Applications / Single-Page-Applications. The framework allows you to easily create complex web applications.

You can dynamically start and stop/destroy modules that acts as small parts of your whole application.

Architecture overview

scaleApp is based on a decoupled, event-driven architecture that is inspired by the talk of Nicholas C. Zakas - "Scalable JavaScript Application Architecture" (Slides). There also is a little Article that describes the basic ideas.

scaleApp architecture

Module

A module is a completely independent part of your application. It has absolutely no reference to another piece of the app. The only thing the module knows is your sandbox. The sandbox is used to communicate with other parts of the application.

Sandbox

The main purpose of the sandbox is to use the facade pattern. In that way you can hide the features provided by the core and only show a well defined custom static long term API to your modules. This is actually one of the most important concept for creating mainainable apps. Change plugins, implementations etc. but keep your API stable for your modules. For each module a separate sandbox will be created.

Core

The core is responsible for starting and stopping your modules. It also handles the messages by using the Publish/Subscribe (Mediator) pattern

Plugin

Plugins can extend the core or the sandbox with additional features. For example you could extend the core with basic functionalities (like DOM manipulation) or just aliases the features of a base library (e.g. jQuery).

Features

loose coupling of modules
small (about 300 sloc / 8,7k min / 3.3k gz)
no dependencies
modules can be tested separately
replacing any module without affecting other modules
extendable with plugins
browser and Node.js support
flow control
AMD & CommonJS support
framework-agnostic

Extendable

scaleApp itself is very small but it can be extended with plugins. There already are some plugins available:

mvc - simple MVC
i18n - multi language UIs
permission - take care of method access
state - Finite State Machine
submodule - cascade modules
dom - DOM manipulation
strophe - XMPP communication
modulestate - event emitter for init and destroy
util - helper methods like mixin, uniqueId etc.
ls - list modules, instances & plugins

You can easily define your own plugin (see plugin section).

Download

Latest stable 0.4.x version

or use the CDN:

<script src="//cdnjs.cloudflare.com/ajax/libs/scaleapp/0.4.4/scaleapp.min.js" ></script>

Old stable 0.3.x version

Note

There are some API changes in version 0.4.x (see Changelog). Docs for v0.3.9 can be found within the tar/zip file.

Unstable version

scaleApp-master.zip

git clone git://github.com/flosse/scaleApp.git

Quick Start

Link scaleApp.min.js in your HTML file:

<script src="scaleApp.min.js"></script>

or use the CDN:

<script src="//cdnjs.cloudflare.com/ajax/libs/scaleapp/0.4.4/scaleapp.min.js" ></script>

If you're going to use it with node:

npm install scaleapp --save

var sa = require("scaleapp");

or use bower:

bower install scaleapp

Create your own Sandbox

First of all create your own sandbox. By doing that you're able to guarantee a stable maintainable API for your modules.

var MySandbox = function(core, instanceId, options, moduleId) {

  // define your API
  this.myFooProperty = "bar";

  // e.g. provide the Mediator methods 'on', 'emit', etc.
  core._mediator.installTo(this);

  // ... or define your custom communication methods
  this.myEmit = function(channel, data){
    core.emit(channel + '/' + instanceId, data);
  };

  // maybe you'd like to expose the instance ID
  this.id = instanceId;

  return this;
};

// ... and of course you can define shared methods etc.
MySandbox.prototype.foo = function() { /*...*/ };

Create a core

Now create a new core instance with your sandbox:

var core = new scaleApp.Core(MySandbox);

Register modules

core.register( "myModuleId", function( sandbox ){
  return {
    init:    function(){ /*...*/ },
    destroy: function(){ /*...*/ }
  };
});

As you can see the module is a function that takes the sandbox as a parameter and returns an object that has two functions init and destroy (the latter is optional). Of course your module can be any usual class with those two functions.

var MyGreatModule = function(sandbox){
  return {
    init:    function(){ alert("Hello world!"); }
    destroy: function(){ alert("Bye bye!");     }
  };
};

core.register("myGreatModule", MyGreatModule);

The init function is called by the framework when the module is supposed to start. The destroy function is called when the module has to shut down.

Asynchronous initialization

You can also init or destroy you module in a asynchronous way:

var MyAsyncModule = function(sandbox){
  return {
    init: function(options, done){
      doSomethingAsync(function(err){
        // ...
        done(err);
      });
    },
    destroy: function(done){
      doSomethingElseAsync(done);
    }
  };
};

core.register("myGreatModule", MyGreatModule);
core.start("myGreatModule", { done:function(){
  alert("now the initialization is done");
}});

Start modules

After your modules are registered, start your modules:

core
  .start( "myModuleId" )
  .start( "anOtherModule", function(err){
    // 'anOtherModule' is running now
  });

Start options

You may also want to start several instances of a module:

core.start( "myModuleId", {instanceId: "myInstanceId" } );
core.start( "myModuleId", {instanceId: "anOtherInstanceId" });

All you attach to options is accessible within your module:

core.register( "mod", function(sandbox){
  return {
    init: function(opt){
      (opt.myProperty === "myValue")  // true
    },
    destroy: function(){ /*...*/ }
  };
});

core.start("mod", {
  instanceId: "test",
  options: { myProperty: "myValue" }
});

If all your modules just needs to be instanciated once, you can simply starting them all:

core.start();

To start some special modules at once you can pass an array with the module names:

core.start(["moduleA","moduleB"]);

You can also pass a callback function:

core.start(function(){
  // do something when all modules were initialized
});

Moreover you can use a separate sandbox for each instance:

var MySandbox = function(){/*...*/};
core.start("module", { sandbox: MySandbox });

Stopping

It's obvious:

core.stop("moduleB");
core.stop(); // stops all running instances

Publish/Subscribe

If the module needs to communicate with others, you can use the emit and on methods.

emit

The emit function takes three parameters whereas the last one is optional:

topic : the channel name you want to emit to
data : the data itself
cb : callback method

The emit function is accessible through the sandbox (as long as you exposed the Mediator methods of course):

sandbox.emit( "myEventTopic", myData );

on

A message handler could look like this:

var messageHandler = function( data, topic ){
  switch( topic ){
    case "somethingHappend":
      sandbox.emit( "myEventTopic", processData(data) );
      break;
    case "aNiceTopic":
      justProcess( data );
      break;
  }
};

... and it can listen to one or more channels:

sub1 = sandbox.on( "somthingHappend", messageHandler );
sub2 = sandbox.on( "aNiceTopic", messageHandler );

Or just do it at once:

sandbox.on({
  topicA: cbA,
  topicB: cbB,
  topicC: cbC
});

You can also subscribe to several channels at once:

sandbox.on(["a", "b"], cb);

If you prefer a shorter method name you can use the alias on.

attache and detache

A subscription can be detached and attached again:

sub.detach(); // don't listen any more
sub.attach(); // receive upcoming messages

Unsubscribe

You can unsubscribe a function from a channel

sandbox.off("a-channel", callback);

ScaleApp

Install / Use

README