@owja/ioc

OWJA! IoC

This library implements dependency injection for javascript. It is currently work in progress and not jet released.

Usage

Step 1 - Install the OWJA! IoC library

npm install --save-dev @owja/ioc

Step 3 - Create symbols for your dependencies

Create a folder ioc and add the new file ioc/types.ts:

export const TYPE = {
    "MyService" = Symbol.for("MyService"),
    "MyOtherService" = Symbol.for("MyOtherService"),
};

Step 2 - Create a container

Next need a container to bind your dependencies to. Lets create the file ioc/container.ts

import {Container, inject} from "@owja/ioc";

import {TYPE} from "./types";

import {IMyService, MyService} from "./service/my-service";
import {IMyOtherService, MyOtherService} from "./service/my-other-service";

const container = new Container();

container.bind<IMyService>(TYPE.MyService).to(MyService);
container.bind<IMyOtherService>(TYPE.MyOtherService).to(MyOtherService);

export {container, TYPE, inject};

Step 3 - Inject your dependency

Lets create a example.ts file in your source root:

import {container, TYPE, inject} from "./ioc/container";
import {IMyService} from "./service/my-service";

class Example {
    
    @inject(TYPE.MyService)
    readonly myService!: IMyService;
    
    @inject(TYPE.MyOtherSerice)
    readonly myOtherService!: IMyOtherService;
    
}

const example = new Example();

console.log(example.myService);
console.log(example.myOtherSerice);

If you run this example you should see the content of your example services.

Unit testing with IoC

You can snapshot and restore a container for unit testing. You can make multiple snapshots in a row, but that is not recommend.

beforeEach(() => {
    container.snapshot();
});

afterEach(() => {
    container.restore();
}

test("can do something", () => {
    container.rebind<MyServiceMock>(TYPE.MySerice).to(MyServiceMock);
    const mock = container.get<MyServiceMock>(TYPE.MySerice);
});

Development

I am working on the first release. Current state can you see in the Github Project.

Inspiration

This library is highly inspired by InversifyJS but has other goals:

1. I want to make a very lightweight solution
2. I want implement less features to be more straight forward
3. Always lazy inject the dependencies

License

License under Creative Commons Attribution 4.0 International

Copyright © 2019 Hauke Broer