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Self

A parameter decorator to be used on constructor parameters, which tells the DI framework to start dependency resolution from the local injector.

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说明

Resolution works upward through the injector hierarchy, so the children of this class must configure their own providers or be prepared for a null result.

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使用说明

In the following example, the dependency can be resolved by the local injector when instantiating the class itself, but not when instantiating a child.

class Dependency {} @Injectable() class NeedsDependency { constructor(@Self() public dependency: Dependency) {} } let inj = Injector.create({ providers: [ {provide: Dependency, deps: []}, {provide: NeedsDependency, deps: [[new Self(), Dependency]]} ] }); const nd = inj.get(NeedsDependency); expect(nd.dependency instanceof Dependency).toBe(true); const child = Injector.create({ providers: [{provide: NeedsDependency, deps: [[new Self(), Dependency]]}], parent: inj }); expect(() => child.get(NeedsDependency)).toThrowError();
      
      
  1. class Dependency {}
  2.  
  3. @Injectable()
  4. class NeedsDependency {
  5.   constructor(@Self() public dependency: Dependency) {}
  6. }
  7.  
  8. let inj = Injector.create({
  9.   providers: [
  10.     {provide: Dependency, deps: []},
  11.     {provide: NeedsDependency, deps: [[new Self(), Dependency]]}
  12.   ]
  13. });
  14. const nd = inj.get(NeedsDependency);
  15.  
  16. expect(nd.dependency instanceof Dependency).toBe(true);
  17.  
  18. const child = Injector.create({
  19.   providers: [{provide: NeedsDependency, deps: [[new Self(), Dependency]]}],
  20.   parent: inj
  21. });
  22. expect(() => child.get(NeedsDependency)).toThrowError();