Class Overview
class ReflectiveInjector {
staticresolve(providers: Provider[]) : ResolvedReflectiveProvider[]
staticresolveAndCreate(providers: Provider[], parent?: Injector) : ReflectiveInjector
staticfromResolvedProviders(providers: ResolvedReflectiveProvider[], parent?: Injector) : ReflectiveInjector
parent : Injector
resolveAndCreateChild(providers: Provider[]) : ReflectiveInjector
createChildFromResolved(providers: ResolvedReflectiveProvider[]) : ReflectiveInjector
resolveAndInstantiate(provider: Provider) : any
instantiateResolved(provider: ResolvedReflectiveProvider) : any
get(token: any, notFoundValue?: any) : any
}
Class Description
A ReflectiveDependency injection container used for instantiating objects and resolving dependencies.
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.
Example (live demo)
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.
Static Members
resolve(providers: Provider[]) : ResolvedReflectiveProvider[]
Turns an array of provider definitions into an array of resolved providers.
A resolution is a process of flattening multiple nested arrays and converting individual providers into an array of ResolvedReflectiveProviders.
@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");
});
See ReflectiveInjector for more info.
resolveAndCreate(providers: Provider[], parent?: Injector) : ReflectiveInjector
Resolves an array of providers and creates an injector from those providers.
The passed-in providers can be an array of Type, Provider, or a recursive array of more providers.
@Injectable()
class Engine {
}
@Injectable()
class Car {
constructor(public engine:Engine) {}
}
var injector = ReflectiveInjector.resolveAndCreate([Car, Engine]);
expect(injector.get(Car) instanceof Car).toBe(true);
This function is slower than the corresponding fromResolvedProviders because it needs to resolve the passed-in providers first. See Injector and Injector.
fromResolvedProviders(providers: ResolvedReflectiveProvider[], parent?: Injector) : ReflectiveInjector
Creates an injector from previously resolved providers.
This API is the recommended way to construct injectors in performance-sensitive parts.
@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);
Class Details
parent : Injector
Parent of this injector.
var parent = ReflectiveInjector.resolveAndCreate([]); var child = parent.resolveAndCreateChild([]); expect(child.parent).toBe(parent);
resolveAndCreateChild(providers: Provider[]) : ReflectiveInjector
Resolves an array of providers and creates a child injector from those providers.
The passed-in providers can be an array of Type, Provider, or a recursive array of more providers.
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));
This function is slower than the corresponding createChildFromResolved because it needs to resolve the passed-in providers first. See Injector and Injector.
createChildFromResolved(providers: ResolvedReflectiveProvider[]) : ReflectiveInjector
Creates a child injector from previously resolved providers.
This API is the recommended way to construct injectors in performance-sensitive parts.
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));
resolveAndInstantiate(provider: Provider) : any
Resolves a provider and instantiates an object in the context of the injector.
The created object does not get cached by the injector.
@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));
instantiateResolved(provider: ResolvedReflectiveProvider) : any
Instantiates an object using a resolved provider in the context of the injector.
The created object does not get cached by the injector.
@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));
get(token: any, notFoundValue?: any) : any
exported from @angular/core/index, defined in @angular/core/src/di/reflective_injector.ts
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