bilbo

bilbo

Bilbo is a simple dependency injection library for JavaScript. It's intended audience is for node-js applications, but it can also be used for client-side applications.

He uses bags to store and distribute dependencies along your code. Bags are identifies by it's name within bilbo.

var bilbo = require("bilbo");
var bag = bilbo.bag("bag's name");

If there is no bag with a given name, bilbo.bag() will create one.

Fetching things from a bag is done by the bag.grab() method. Each thing is identified by it's name within the bag.

var thing = bag.grab("thing's name");

Bags can store things in many ways:

• stuff: simple storage, no action performed
• prototype: stores a prototype object used to create new objects having this one as prototype
• factory: stores a function to be used as factory each time
• lazy: stores a function that initializes an returns something that may be returned every time
• type: stores a constructor function that may be used for creating new instances each time
• singleton: stores a constructor function that may be used for create a single instance

stuff

Just stores something within the bag itself. No modification whatsoever is taken upon the stored data.

var myStuff = {};
 // stores myStuff under "stuff's name"
bag.stuff("stuff's name", myStuff);

// grabs back myStuff using "stuff's name"
var myStuffBack = bag.grab("stuff's name");

myStuff === myStuffBack; // true

prototype

Stores a prototype object. This object will be used as prototype for a newly created object each time bag.grab() is called.

var myPrototype = { a: {} };
// stores myPrototype under "prototype's name"
bag.prototype("prototype's name", myPrototype);

// grabs a new object having myPrototype as prototype using "prototype's name"
var myObject = bag.grab("prototype's name");

myObject.a === myPrototype.a; // true
myObject.hasOwnProperty("a"); // false

factory

Stores a factory function. This function will be used to create new things each time bag.grab() is called.

var myFactory = function() { return {}; };
// stores myFactory under "factory's name"
bag.factory("factory's name", myFactory);

// grabs oneThing created by the myFactory function
var oneThing = bag.grab("factory's name");
// grabs anotherThing created by the myFactory function
var anotherThing = bag.grab("factory's name");

oneThing === anotherThing; // false

lazy

Stores a lazy function. This function will be used only once to create a new thing when bag.grab() is called. Subsequent calls will return the same thing created the first time it was called.

var myLazy = function() { return {}; };
// stores myLazy under "lazy's name"
bag.lazy("lazy's name", myLazy);

// grabs a thing created by the myLazy function
var thing = bag.grab("lazy's name");
// grabs the sameThing created by the myLazy function previously
var sameThing = bag.grab("lazy's name");

thing === sameThing; // true

type

Stores a type constructor function. This function will be used as a constructor to create new type instances each time bag.grab() is called.

var MyConstructor = function() {};
// stores MyConstructor under "type's name"
bag.type("type's name", MyConstructor);

// grabs anInstance created by the MyConstructor function
var anInstance = bag.grab("type's name");
// grabs anotherInstance created by the MyConstructor function
var anotherInstance = bag.grab("type's name");

anInstance === anotherInstance; // false
anInstance instanceof MyConstructor; // true
anotherInstance instanceof MyConstructor; // true

singleton

Stores a type constructor function as a singleton. This function will be used as a singleton constructor to create a singleton instance once bag.grab() is called. Subsequent calls yields the same singleton instance.

var MySingletonConstructor = function() {};
// stores MySingletonConstructor under "singleton's name"
bag.singleton("singleton's name", MySingletonConstructor);

// grabs aSingleton created by the MySingletonConstructor function
var aSingleton = bag.grab("singleton's name");
// grabs sameSingleton created by the MySingletonConstructor function previously
var sameSingleton = bag.grab("singleton's name");

aSingleton === sameSingleton; // true
aSingleton instanceof MySingletonConstructor; // true