simple-ts-di

Simple DI framework written in and for TypeScript. By default all bindings are in singleton scope. Where possible you can call a transient() binder function to create a transient binding.

Setup

Make sure your tsconfig.json contains

{
  "experimentalDecorators": true,
  "emitDecoratorMetadata": true
}

Install reflect-metadata and include it somewhere.

Make sure your setup supports Maps and Symbols.

Example

Constructor injection

class Service {
  sayHi() { return 'hi'; }
}
 
@inject()
class Test {
  constructor(service: Service) {
    service.sayHi();
  }
}
 
class MyModule implements Module {
  init(bind: Bind) {
    bind(Service).transient(); // transient scope
    bind(Test); // singleton scope
                // shortcut for bind(Test).to(Test)
  }
}
 
const container = new Container(new MyModule());
const test = container.get(Test);

Property injection

simple-ts-di supports property injection. It will only work if the type (here Service) has a meaningful runtime representation. So it only works for classes (as of now). If you want to inject some primitives or a service which implements an interface you have to use named injection. If your environment dont let you control how the class is instantiated (e.g. react components are instantiated by react and not via container.get(...)), you can use a special version of inject - abounded inject. See "bounded property injection".

class Service {
  sayHi() { return 'hi'; }
}
 
class Test {
  @inject()
  private service: Service;
 
  sayHelloToService() {
    return this.service.sayHi();
  }
}
 
class MyModule implements Module {
  init(bind: Bind) {
    bind(Service).transient(); // transient scope
    bind(Test); // singleton scope
                // shortcut for bind(Test).to(Test)
  }
}
 
const container = new Container(new MyModule());
const test = container.get(Test);

named injection

const SERVICE = Symbol();
const PRIMITIVE = Symbol();
 
interface IService {
  sayHi(): string;
}
 
class Service implements IService {
  sayHi() { return 'hi'; }
}
 
@inject([SERVICE, PRIMITIVE])
class Test {
  @inject(SERVICE)
  private service: IService;
 
  @inject(PRIMITIVE)
  private primitive: number;
 
  constructor(service: IService, primitive: number) {
  }
}
 
class MyModule implements Module {
  init(bind: Bind) {
    bind(SERVICE).to(Service);
    bind(PRIMITIVE).toValue(10);
    bind(Test);
  }
}
 
const container = new Container(new MyModule());
const test = container.get(Test);

bounded property injection

class Service {
  sayHi() {
    return 'hi';
  }
}
 
class MyModule implements Module {
  init(bind: Bind) {
    bind(Service);
  }
}
 
const container = new Container(new MyModule());
const bInject = createBoundedInject(container);
 
class Test {
  @bInject() service: Service;
}
 
const t = new Test();
 
t.service.sayHi(); // returns Hi

See tests/ for more complex examples and API.