javascript - Angular 2在订阅方法中设置值问题

Question

这个问题已经有答案了:

How do I return the response from an Observable/http/async call in angular? (10 个回答)

已关闭 6 年前。

我正在服务器上发表一篇文章，并尝试控制台输出响应http代码。我使用 chrome 工具作为调试器来检查响应，我可以看到输出，但最后它会订阅库执行某些操作并设置函数而不是值。

My component class is

 export class MicroserviceCreateComponent implements OnInit{

   errorMessage: string;
   postMessage: string;
   teams: Team[];
   microservice: Microservice[];

    constructor(private microserviceService: MicroserviceService) { }

    ngOnInit() {
    }

  onSubmit({ value, valid }: { value: Microservice, valid: boolean }) {
     this.createMicroservice(value); 
     console.log(this.postMessage); <<<<<<<<==== This gives me undefined
  }

   createMicroservice(value){
      this.microserviceService.createMicroservice(value).subscribe(
        postMessage => this.postMessage = postMessage.valueOf(),
         error => {
          this.errorMessage = error.getMessage();
          console.error(error.getDescription());
        });
  }
}

Answer 1

this.microserviceService.createMicroservice(value).subscribe(...) 是一个非阻塞异步调用。这意味着在您调用它之后，可以在 Web 请求完成之前自由打印 console.log(this.postMessage)。尝试将 console.log(this.postMessage) 放入订阅中。

this.createMicroservice(value); // This is an async call
console.log(this.postMessage); // This happens immediately afterwards