如何从angular4（ionic3）的服务提供者组件传递响应给父组件，我得到了未定义的值？

Question

in parent component i got undefined value for data. here is my code.

parentComponent.ts

testMethod(){
  console.log('t', this.answer.postRequest(this.quetion).subscribe(data => { 
    console.log('d',data);
  })); //here i got undefined value to data
}

serviceProvider.ts

postRequest(ques:string):Observable<any>{
  let header = new HttpHeaders({
    'Content-Type' : 'application/json',"Accept":'application/json'
  });
  console.log(ques)

  return this.http.post(
    "http://localhost:8080/hello",
    {'q': ques},
    {headers: header}
  ).map(data => {
    console.log(data);
  }, // this work fine and value is assigned to data as expected
  error => {(error);// Error getting the data});
}

Answer 1

use like this

return this.http.post(" http://localhost:8080/hello ",{ 'q': ques },{ headers:header}) .map(data => { console.log(data); }) .map((resp: Response) => {return resp;});

it will helps