Retrieve data from a ReadableStream object?

fetch-api, javascript

Solution

In order to access the data from a `ReadableStream` you need to call one of the conversion methods (docs available here).

As an example:

fetch('https://jsonplaceholder.typicode.com/posts/1')
  .then(function(response) {
    // The response is a Response instance.
    // You parse the data into a useable format using `.json()`
    return response.json();
  }).then(function(data) {
    // `data` is the parsed version of the JSON returned from the above endpoint.
    console.log(data);  // { "userId": 1, "id": 1, "title": "...", "body": "..." }
  });

EDIT: If your data return type is not JSON or you don't want JSON then use `text()`

As an example:

fetch('https://jsonplaceholder.typicode.com/posts/1')
  .then(function(response) {
    return response.text();
  }).then(function(data) {
    console.log(data); // this will be a string
  });

Problem

How may I get information from a `ReadableStream` object? I am using the Fetch API and I don't see this to be clear from the documentation. The body is being returned as a `ReadableStream` and I would simply like to access a property within this stream. Under Response in the browser dev tools, I appear to have this information organised into properties, in the form of a JavaScript object. ``` fetch('http://192.168.5.6:2000/api/car', obj) .then((res) => { if(!res.ok) { console.log("Failure:" + res.statusText); throw new Error('HTTP ' + res.status); } else { console.log("Success :" + res.statusText); return res.body // what gives? } }) ```

Original source