A ReflectiveDependency injection container used for instantiating objects and resolving dependencies.

See more...

Deprecated: from v5 - slow and brings in a lot of code, Use Injector.create instead.

abstract class ReflectiveInjector implements Injector {
  static resolve(providers: Provider[]): ResolvedReflectiveProvider[]
  static resolveAndCreate(providers: Provider[], parent?: Injector): ReflectiveInjector
  static fromResolvedProviders(providers: ResolvedReflectiveProvider[], parent?: Injector): ReflectiveInjector
  abstract parent: Injector | null
  abstract resolveAndCreateChild(providers: Provider[]): ReflectiveInjector
  abstract createChildFromResolved(providers: ResolvedReflectiveProvider[]): ReflectiveInjector
  abstract resolveAndInstantiate(provider: Provider): any
  abstract instantiateResolved(provider: ResolvedReflectiveProvider): any
  abstract get(token: any, notFoundValue?: any): any
}

Description

An Injector is a replacement for a new operator, which can automatically resolve the constructor dependencies.

In typical use, application code asks for the dependencies in the constructor and they are resolved by the Injector.

Further information is available in the Usage Notes...

Static methods

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var providers = ReflectiveInjector.resolve([Car, [[Engine]]]);

expect(providers.length).toEqual(2);

expect(providers[0] instanceof ResolvedReflectiveProvider).toBe(true);
expect(providers[0].key.displayName).toBe("Car");
expect(providers[0].dependencies.length).toEqual(1);
expect(providers[0].factory).toBeDefined();

expect(providers[1].key.displayName).toBe("Engine");
});

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var injector = ReflectiveInjector.resolveAndCreate([Car, Engine]);
expect(injector.get(Car) instanceof Car).toBe(true);

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var providers = ReflectiveInjector.resolve([Car, Engine]);
var injector = ReflectiveInjector.fromResolvedProviders(providers);
expect(injector.get(Car) instanceof Car).toBe(true);

Properties

Methods

class ParentProvider {}
class ChildProvider {}

var parent = ReflectiveInjector.resolveAndCreate([ParentProvider]);
var child = parent.resolveAndCreateChild([ChildProvider]);

expect(child.get(ParentProvider) instanceof ParentProvider).toBe(true);
expect(child.get(ChildProvider) instanceof ChildProvider).toBe(true);
expect(child.get(ParentProvider)).toBe(parent.get(ParentProvider));

class ParentProvider {}
class ChildProvider {}

var parentProviders = ReflectiveInjector.resolve([ParentProvider]);
var childProviders = ReflectiveInjector.resolve([ChildProvider]);

var parent = ReflectiveInjector.fromResolvedProviders(parentProviders);
var child = parent.createChildFromResolved(childProviders);

expect(child.get(ParentProvider) instanceof ParentProvider).toBe(true);
expect(child.get(ChildProvider) instanceof ChildProvider).toBe(true);
expect(child.get(ParentProvider)).toBe(parent.get(ParentProvider));

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var injector = ReflectiveInjector.resolveAndCreate([Engine]);

var car = injector.resolveAndInstantiate(Car);
expect(car.engine).toBe(injector.get(Engine));
expect(car).not.toBe(injector.resolveAndInstantiate(Car));

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var injector = ReflectiveInjector.resolveAndCreate([Engine]);
var carProvider = ReflectiveInjector.resolve([Car])[0];
var car = injector.instantiateResolved(carProvider);
expect(car.engine).toBe(injector.get(Engine));
expect(car).not.toBe(injector.instantiateResolved(carProvider));

Usage notes

Example

The following example creates an Injector configured to create Engine and Car.

@Injectable()
class Engine {
}

@Injectable()
class Car {
  constructor(public engine:Engine) {}
}

var injector = ReflectiveInjector.resolveAndCreate([Car, Engine]);
var car = injector.get(Car);
expect(car instanceof Car).toBe(true);
expect(car.engine instanceof Engine).toBe(true);

Notice, we don't use the new operator because we explicitly want to have the Injector resolve all of the object's dependencies automatically.

TODO: delete in v14.