从 Class 装饰器中访问注入的服务？打字稿/ NestJS

Question

是否可以从 Class 装饰器中访问注入的服务？

我想在自定义构造函数中获取服务：

function CustDec(constructor: Function) {
  var original = constructor;

  var f: any = function (...args) {
    // I want to get injectedService here. How?
    // I've tried things like this.injectedService but that doesn't work
    return new original(...args);
  }

  f.prototype = target.prototype;
  return f;
}

@CustDec
@Injectable()
class MyService {
  constructor(
    private readonly injectedService: InjectedService,
  ) {}
}

Answer 1

基于 official class-decorator docs，这里有一个应该可行的方法：

function CustDec<T extends new(...args: any[]) => {}>(Target: T) {
    return class extends Target {
        constructor(...args: any[]) {
            super(...args);
            (args[0] as InjectedService).doSomething();
        }
    }
}

@CustDec
@Injectable()
class MyService {
  constructor(
    private readonly injectedService: InjectedService,
  ) {}
}

我还在 TS-Playground 上创建了一个示例。

从 Class 装饰器中访问注入的服务？打字稿/ NestJS

Access an injected service from within a Class decorator? Typescript / NestJS

decorator

typescript

nestjs