konoha v1.0.3

Konoha

Konoha is Dependency Injection Container that allows you take the advantage of the dependency injection principle in Javascript.

Installation

npm install --save konoha

Getting Started

First we need to create a new instace of Konoha. After that we can use methods like set and get to access it.

Using ES6

import Konoha from 'konoha';

class Application extends Konoha {
    constructor() {
        super();
        this.set('isValid', true);
        this.set('user', {
            name: 'User Name',
            permissions: []
        });
        this.set('api', function() {
            return new Api();
        });

        this.get('api').post('/dummy/data');

        ...
    }
}

Pre-ES6 (NodeJS or CommonJS)

var Konoha = require('konoha');
var app = new Konoha();

// you can chain any of the API methods
app.set('isValid', true)
    .set('user', {
        name: 'User Name',
        permissions: []
    })
    .set('api', function() {
        return new Api();
    });

app.get('api').post('/dummy/data');

API

get(name)

Gets the value by the name.

app.set('isValid', false);
app.set('foo', function() { return 'bar'; });

app.get('isValid'); // false
app.get('foo'); // 'bar'

set(name, value)

Sets a new attribute with given value.

You can set anything on the value. If the value is a function it will only be constructed/called once but it won't called until it is requested by get. The function context will be the app, so you access to the app if you need it. This shouldn't be used for setting/binding class definitions. Only the class intances should be stored.

app.set('isValid', true);
app.set('user', {
    name: 'Full Name',
    isActive: true,
    permissions: []
});

// sets an API service
app.set('api.prefix', '/api');
app.set('api', function() {
    return new Api(this.get('api.prefix'));
});

var isValid = app.get('isValid');
var user = app.get('user');

// get API service
// This will initiate a new instance of the API
var api = app.get('api');
api.get('/some/rest/api');

// This time it will use existing API instance, since the function only gets called once
var api = app.get('api');

has(name)

Checks if there is anything registered under given name.

app.has('version'); // false

app.set('version', '4.3.2');

app.has('version'); // true

keys()

Get all the registered names as an array.

app.set('version', '4.3.2');
app.set('isValid', true);

app.keys(); // ['version', 'isValid']

raw(name)

Returns the original definition of the service.

app.set('api', function() {
    return new Api();
});

var api = app.raw('api'); // the callback/function definition

extend(name, callback)

Allows you to extend/modify the registered service

Let's add a response handler to the API service that converts the response to JSON. To do that we need to pass a function that takes one argument which will be the current value of the existing service. It should return a new value that will replace the existing value.

app.set('api', function() {
    return new Api();
});

app.extend('api', function(api) {
    api.addResponseHandler(new JsonResponse());
    return api;
});

Now every response you get should be converted into JSON.

factory(name, service)

Not everytime you want to get the cached (constructed) service. Use factory to create a service that will be reconstructed/called everytime it gets requested by get.

app.factory('person', function() {
    return new Person();
});

// Creates new Person instance
var person1 = app.get('person');

// Creates new Person instance again
var person2 = app.get('person');

protect(name, value)

Unlike set or factory which always returns the value of the service/function the protect allows you define a service/function that will never called by get. It's something that is needed if you want to store something without getting modified by get. The protect will always return the definition of the service/function.

app.protect('person', function(name) {
    var person = new Person(name);
    return person;
});

app.get('person'); // will return the function that takes a name argument

var siri = app.get('person')('Siri');
console.log(siri.getName()); // 'Siri'

var alexa = app.get('person')('Alexa');
console.log(alexa.getName()); // 'Alexa'

register(provider)

This function allows you to register services in bulk. The provider function that is passed doesn't become a service. But it gets called immediately.

app.register(function() {
    this.set('logger.level', 'debug');
    this.set('logger', function() {
        return new Logger(this.get('logger.level'));
    });
});