当 Inject-able class 的函数作为参数发送到另一个模块时，"this" 未定义

Question

这就是我想要做的，我将函数引用从 Provider1（存在于模块 1 中）传递给 Provider2（存在于模块 2 中）。当我尝试调用该函数时，“this”的值未定义。知道可能出了什么问题吗？

Module1.ts

@Module({
  controllers: [Controller1],
  providers: [Provider1],
})
export class Module1{}

Provider1.ts

@Injectable()
export class Provider1 {
  constructor(private readonly provider2: Provider2) {} 
  providerFunction() {
    this.provider2.provider2Function(new HelperClass().helperFunction);
  }
}

HelperClass.ts

@Injectable()
export class HelperClass {
  helperFunction() {
    return this.someValue; //Here, this is undefined
  }
}

Provider2.ts

@Injectable()
export class Provider2 {
  provider2Function(helperFunction: ()=>void) {
    console.log(helperFunction());
  }
}

Answer 1

这是因为 this 以这种方式传递方法时发生了变化。像这样尝试：

@Injectable()
export class Provider1 {
  constructor(private readonly provider2: Provider2) {} 
  providerFunction() {
    const helper = new HelperClass();
    this.provider2.provider2Function(helper.helperFunction.bind(helper));
  }
}

详细了解 this 关键字的工作原理 here。

当 Inject-able class 的函数作为参数发送到另一个模块时，"this" 未定义

"this" is undefined when function of an Inject-able class is sent as argument to another module

typescript

class

dependency-injection

nestjs

nestjs-config