角度得到反应的身体

Question

I'm having trouble understanding how one is supposed to get the response body from an Angular Response object. In their docs they have an example that states

http.request('my-friends.txt').subscribe(response => this.friends = response.text());

yet when I attempt to do let body: string = response.text(); I get an error saying "Argument of type 'Promise' is not assignable to parameter of type 'string'".

I tried treating it as a promise and doing

let body: string; response.text().then(text => body = text);

which removes the compilation error, but when this code gets invoked it throws and error saying "TypeError: response.text(...).then is not a function".

I would like to understand what exactly a Promise is and how I need to retrieve it's properties.

Answer 1

I believe you've referenced the wrong Response object in your imports. If you're specifying the type need to import Response object from Angular package:

import { Response } from '@angular/http`;

There is also Response object from fetch API supported natively by browsers. They differ in that Angular Response object returns string for Response.text() method, while fetch API Response returns a promise. The http service uses Angular's Response object and it returns a string so you don't need a promise here.

If you want to save the body text to the body variable, you have to do it when you get the value from an observable:

http.request('my-friends.txt').subscribe((response: Response) => this.body = response.text());