Dependency Injection

Dependency Injection (DI) is a design pattern used to implement IoC.
Learn more about dependency injector in fundamentals section.
You can use DI lib in any of your projects.

Installing

npm i @typeix/di --save

Injector API

All providers are immutable, however you can define mutable provider keys.
If provider is not mutable, and you are trying to create new instance of same provider on current Injector instance, injector will throw error.

Injector.getProviders(provider: IProvider, propertyKey?: string) will return all providers which needs to be injected, if propertyKey is not defined injector will return providers for constructor.

Injector.getAllMetadataForTarget(provider: IProvider) will return all metadata, injector cache them internally. Works with class provider only.

import {Injectable, Injector, Inject} from "@typeix/di";

Injector.createAndResolve(ServiceA, [
  ServiceB
]).then(injector => {
  let service = injector.get(ServiceA);
  return service.getName();
});

Async API:

class Injector {
    constructor(_parent?: Injector, keys?: Array<any>);
    static getProviders(provider: IProvider, propertyKey?: string): Array<IProvider>;
    // returns all metadata for provider
    static getAllMetadataForTarget(provider: IProvider): Array<IMetadata>;
    // creates new child injector, provider and providers
    static createAndResolveChild(parent: Injector, Class: MixedProvider, providers: Array<MixedProvider>): Promise<Injector>;
    // creates new injector, provider and providers+-
    static createAndResolve(Class: MixedProvider, providers: Array<MixedProvider>): Promise<Injector>;
    // creates new provider and providers
    createAndResolve(provider: IProvider, providers: Array<IProvider>): Promise<any>;
    // clens current injectables and all child injectors & providers
    destroy(): void;
    // check if providier exists on current Injector instance
    has(key: any): boolean;
    // get provider value from current Injector if not found bubble parrent's
    // if not found on any of parents exception is thrown.
    get(provider: string, Class?: IProvider): any;
    get<T>(provider: Type<T>, Class?: IProvider): T;
    // set provider and value
    set(key: any, value: Object): void;
    getParent(): Injector;
    setParent(injector: Injector): void;
    setName(provider: IProvider): void;
    hasChild(injector: Injector): boolean;
    addChild(injector: Injector): this;
}

Sync Injector API

Since version 8.x default Injector behavior is converted to async API, if you want to use sync api you need to use Injector.Sync.createAndResolve or Injector.Sync.createAndResolveChild difference is that Async API supports Async providers, it's allowed to use of async/await in factory and return Promises in value provider!

import {Injectable, Injector, Inject} from "@typeix/di";

let injector = Injector.Sync.createAndResolve(ServiceA, [
  ServiceB
]);

let service = injector.get(ServiceA);
service.getName();

Sync API:

class SyncInjector {
  constructor(_parent?: Injector, keys?: Array<any>);
  static getProviders(provider: IProvider, propertyKey?: string): Array<IProvider>;
  // returns all metadata for provider
  static getAllMetadataForTarget(provider: IProvider): Array<IMetadata>;
  // creates new child injector, provider and providers
  static createAndResolveChild(parent: Injector, Class: Function | IProvider, providers: Array<MixedProvider>): Injector;
  // creates new injector, provider and providers
  static createAndResolve(Class: Function | IProvider, providers: Array<MixedProvider>): Injector;
  // creates new provider and providers
  createAndResolve(provider: IProvider, providers: Array<IProvider>): any;
  // clens current injectables and all child injectors & providers
  destroy(): void;
  // check if providier exists on current SyncInjector instance
  has(key: any): boolean;
  // get provider value from current SyncInjector if not found bubble parrent's
  // if not found on any of parents exception is thrown.
  get(provider: string, Class?: IProvider): any;
  get<T>(provider: Type<T>, Class?: IProvider): T;
  // set provider and value
  set(key: any, value: Object): void;
  getParent(): Injector;
  setParent(injector: Injector): void;
  setName(provider: IProvider): void;
  hasChild(injector: Injector): boolean;
  addChild(injector: Injector): this;
}