Inverter

A tiny Inversion of Control (IoC) container for Meteor. This package will help you write decoupled code which means reusable and testable code.

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Installation

meteor add xolvio:inverter

Use Inverter for Code Reuse

Using register/set and get

You can reuse the same events in multiple templates. For example:

Inverter.register('common.events', {
  'click button': function (e) {
    $('#log').html('Clicked: ' + e.target.nodeName);
  }
});

Template.myTemplate.events(Inverter.get('common.events'));
Template.anotherTemplate.events(Inverter.get('common.events'));

Note that set is an alias for register.

Inline get

The register method returns the object you registered so you can use it inline like this:

Template.myTemplate.helpers(Inverter.register('common.helpers', {
  buttonName : function () {
    return 'buttonz'
  }
}));

// reuse common helpers in another template
Template.anotherTemplate.helpers(Inverter.get('common.helpers'));

Passing a context using getWith

You can also pass in a context to use in the common code using the getWith call:

Inverter.register('common.events', {
  'click button': function (e) {
    $('#log').html('Clicked: ' + this.logVar);
  }
});

Template.myTemplate.events(Inverter.getWith('common.events', {'logVar': 'log1'}));
Template.anotherTemplate.events(Inverter.getWith('common.events', {'logVar': 'log2'}));

Use Inverter for Testing

When you write a test, it's difficult to grab the 'click button' event from a unit or integration test. This is where Inverter comes in. You isolate events like this:

Template.myTemplate.events(Inverter.register('myTemplate.events', {
  'click button': function (e) {
    $('#log').html('Clicked: ' + e.target.nodeName);
  }
}));

And now in your test, you can access the events like this:

describe('MyTemplate events', function() {
  it('should do something when the button is clicked', function() {
    
    // SETUP
    $('#log').html('');
    
    // EXCECUTE
    var clickButtonEvent = Inverter.get('myTemplate.events')['click button'];
    var event = { target : { nodeName: 'hello' } };
    clickButtonEvent(event);
  
    // VERIFY
    var logText = $('#log').text();
    expect(logText).toBe('Clicked: BUTTON');
  });
});

Use Your Namespace

MyApp.container = Inverter;

var clickButtonEvent = MyApp.container.get(...);

Multiple Containers

You may want to do this

MyApp.developmentContainer = new Inverter.Container();
MyApp.productionContainer = new Inverter.Container();

// Now you can set the main app container to be dependant on an environment variable

var env = process.env.NODE_ENV;
MyApp.container = MyApp[env + 'Container'];

This allows you have a different configuration for a different environments.

That's it

These are some uses of Inverter. There can be many more cases where you need a pattern for reuse or isolation.

All feedback welcome!