Angular 如何从url中获取数据并将其保存在变量中

大家好，我正在尝试从URL获取数据并将数据保存在变量中，我需要该变量及其值

这是我的服务

import {Injectable} from '@angular/core';
import {HttpClient, HttpErrorResponse} from "@angular/common/http";



const route: string = "http://localhost:51044/api/";

export enum userActions{
  signin,
  signup,
}


interface DataResponse {
  result: boolean;
  accessCode: string;
}

@Injectable({
  providedIn: 'root'
})
export class TaskPlusPlusControllerService {



  constructor(private http: HttpClient) {
  }


  public FetchData(properties: string, action: userActions)
  {
    switch (action)
    {
      case userActions.signin:
        this.getListOfGroup('signin/' + properties);
      break;
      case userActions.signup:
        break;
    }
  }


  private getListOfGroup(url: string) {
    let fetchedData: DataResponse = {result: null,accessCode: ''};
    this.http.get(route + url).subscribe(
      (res) => {
        console.log(res);
        console.log(res['result']);
        console.log(res['accessCode']);
        //fetchedData = res;
        fetchedData.result = res['result'];
        fetchedData.accessCode = res['accessCode'];
      }
    );
    console.log(fetchedData);
  }
}

因此，我直接从

res

获取控制台中的数据，但是当我记录

fetchedData

时，它的值没有改变

---

我应该怎么做呢？

javascript是一种异步编程语言。您必须在subscribe方法中执行console.log操作

private getListOfGroup(url: string) {
    let fetchedData: DataResponse = {result: null,accessCode: ''};
    this.http.get(route + url).subscribe(
      (res) => {
        console.log(res);
        console.log(res['result']);
        console.log(res['accessCode']);
        //fetchedData = res;
        fetchedData.result = res['result'];
        fetchedData.accessCode = res['accessCode'];

        // move here
        console.log(fetchedData);
      }
    );
   // remove from here
   console.log(fetchedData);
  }

---

Javascript是一种单线程异步语言。调用承诺时，它不能是范围外的引用（只在{}内引用结果a承诺的值）。 如果要对另一个函数使用

fetchedData

。试试这个：

import {Injectable} from '@angular/core';
    import {HttpClient, HttpErrorResponse} from "@angular/common/http";
    
    
    
    const route: string = "http://localhost:51044/api/";
    
    export enum userActions{
      signin,
      signup,
    }
    
    
    interface DataResponse {
      result: boolean;
      accessCode: string;
    }
    
    @Injectable({
      providedIn: 'root'
    })
    export class TaskPlusPlusControllerService {
    
      fetchedData: DataResponse = null;
    
      constructor(private http: HttpClient) {
          this.fetchedData = {result: null,accessCode: ''};
      }
    
    
      public FetchData(properties: string, action: userActions)
      {
        switch (action)
        {
          case userActions.signin:
            this.getListOfGroup('signin/' + properties);
          break;
          case userActions.signup:
            break;
        }
      }
    
    
      private getListOfGroup(url: string) {
        let fetchedData: DataResponse = {result: null,accessCode: ''};
        this.http.get(route + url).subscribe(
          (res) => {
            console.log(res);
            console.log(res['result']);
            console.log(res['accessCode']);
            //fetchedData = res;
            this.fetchedData.result = res['result'];
            this.fetchedData.accessCode = res['accessCode'];
          }
        );
      }
    }

这里是答案顺便说一句，现在我可以在我的服务之外的组件中获取我的数据，如下所示

this.data = this.taskPlusPlusAPI.FetchData(this.phoneNumber,userActions.signin);
     this.data.then(value => {
       console.log(value);
     })

---

http get请求是异步的，您在subscribe之外声明了一个变量，并且控制台也在subscribe之外记录它。。。尝试将console.log（fetchedData）放在订阅的末尾

this.data = this.taskPlusPlusAPI.FetchData(this.phoneNumber,userActions.signin);
     this.data.then(value => {
       console.log(value);
     })