Injector
Class
stable
Concrete injectors implement this interface. Injectors are configured with providers that associate dependencies of various types with injection tokens.
get
4 overloadsRetrieves an instance from the injector based on the provided token.
@paramnotFoundValue
undefined
@returns
T
Retrieves an instance from the injector based on the provided token.
@paramnotFoundValue
null | undefined
@returns
T | null
Retrieves an instance from the injector based on the provided token.
@paramnotFoundValue
T | undefined
@returns
T
THROW_IF_NOT_FOUND
{}
NULL
Injector
create
2 overloadsCreates a new injector instance that provides one or more dependencies,
according to a given type or types of StaticProvider
.
@paramoptions
{ providers: (any[] | TypeProvider | ValueProvider | ClassProvider | ConstructorProvider | ExistingProvider | FactoryProvider | StaticClassProvider)[]; parent?: Injector | undefined; name?: string | undefined; }
An object with the following properties:
providers
: An array of providers of the StaticProvider type.parent
: (optional) A parent injector.name
: (optional) A developer-defined identifying name for the new injector.
@returns
DestroyableInjector
Usage Notes
The following example creates a service injector instance.
class Square {
name = 'square';
}
const injector = Injector.create({providers: [{provide: Square, deps: []}]});
const shape: Square = injector.get(Square);
expect(shape.name).toEqual('square');
expect(shape instanceof Square).toBe(true);
Usage example
const injector: Injector = Injector.create({
providers: [{provide: 'validToken', useValue: 'Value'}],
});
expect(injector.get('validToken')).toEqual('Value');
expect(() => injector.get('invalidToken')).toThrowError();
expect(injector.get('invalidToken', 'notFound')).toEqual('notFound');
Injector
returns itself when given Injector
as a token:
const injector = Injector.create({providers: []});
expect(injector.get(Injector)).toBe(injector);
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