container-ioc

!alt text

container-ioc

is a Dependency Injection / Inversion of Control (IoC) container package for Javascript and Node.js applications powered by Typescript . It manages the dependencies between classes, so that applications stay easy to change and maintain as they grow.


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* Well-known Angular DI API.
* No external dependencies.
* Life Time control.
* Hierarchical containers.
* Resolves values using Classes, Factories and Values.
* Descriptive error messages.
* 97% test coverage.

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* examples/javascript
* examples/typescript

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``
npm install --save container-ioc
`

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> Code examples below are written in Typescript. Check examples/javascript for examples written in Javascript.

#### Step 1. Define your interfaces and types.
> Possible values for types: Symbol, string, Object.

`typescript
interface IApplication {
run(): void;
}

interface IService {
serve(): void;
}

const TApplication = Symbol('IApplication');

const TService = Symbol('IService');
`

#### Step 2. Declare dependencies with decorators Injectable and Inject.

`typescript
import { Injectable, Inject } from 'container-ioc';

@Injectable()
export class Application implements IApplication {
constructor(@Inject(TService) private service: IService) {}

run(): void {
this.service.serve();
}
}

@Injectable()
export class Service implements IService {
serve(): void {
// serves
}
}
`

#### Step 3. Create a container and register types in there.

`typescript
import { Container } from 'container-ioc';

let container = new Container();

container.register([
{ token: TApplication, useClass: Application },
{ token: TService, useClass: Service }
]);
`

#### Step 4. Resolve value from the container.

`typescript
let app = container.resolve(TApplication);

app.run();
`

#### Step 2 for Javascript.
> Since Javascript does not support parameter decorators, use alternative API for declaring dependencies. In this case we don't use Inject decorator. See examples/javascript for more.
`javascript

@Injectable([TService])
class Service {
constructor(service) {
this.service = service;
}
}
`

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> By default, containers resolve singletons when using useClass and useFactory.
Default life time for all items in a container can be set by passing an option object to it's contructor with defailtLifeTime attribute. Possible values: LifeTime.PerRequest (resolves instances) and LifeTime.Persistent (resolves singletons);

`typescript
import { LifeTime } from 'container-ioc';

const container = new Container({
defaultLifeTime: LifeTime.PerRequest
});
`
> You can also specify life time individually for each item in a container by specifying lifeTime attribute.

`typescript
container.register([
{
token: TService,
useClass: Service,
lifeTime: LifeTime.PerRequest
}
]);
`
`typescript
container.register([
{
token: TService,
useFactory: () => {
return {
serve(): void {}
}
},
lifeTime: LifeTime.Persistent
}
]);
`

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> If a container can't find a value within itself, it will look it up in ascendant containers. There a 3 ways to set a parent for a container.

###### 1. Container.createChild() method.
`typescript
const parentContainer = new Container();
const childContainer = parentContainer.createChild();
`

###### 2. Container.setParent() method.
`typescript
const parent = new Container();
const child = new Container();

child.setParent(parent);
`

###### 3. Via Container's constructor with options.
`typescript
const parent = new Container();
const child = new Container({
parent: parent
});
`

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`typescript
/ Without injections /
container.register([
{
token: 'TokenForFactory',
useFactory: () => {
return 'any-value';
}
}
]);

/ With injections /
container.register([
{ token: 'EnvProvider', useClass: EnvProvider },
{
token: 'TokenForFactory',
useFactory: (envProvider) => {
// do something
return 'something';
},
inject: ['EnvProvider']
}
]);
`

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`typescript
container.register([
{ token: 'IConfig', useValue: {}}
]);
`

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`typescript
container.register([
App
]);
`
Is the same as:
`typescript
container.register([
{ token: App, useClass: App }
]);
``

Contribution

Become a contributor to this project. Feel free to submit an issue or a pull request.

see CONTRIBUTION.md for more information.

Please see also our Code of Conduct.