javascript - fetch gives an empty response body

Question

I have a react/redux application and I'm trying to do a simple GET request to a sever:

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
}).then((response) => {
  console.log(response.body); // null
  return dispatch({
    type: "GET_CALL",
    response: response
  });
})
.catch(error => { console.log('request failed', error); });

The problem is that the response body is empty in the .then() function and I'm not sure why. I checked examples online and it looks like my code should work so I'm obviously missing something here. The thing is, if I check the network tab in Chrome's dev tools, the request is made and I receive the data I'm looking for.

Can anybody shine a light on this one?

EDIT:

I tried converting the reponse.

using .text():

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
})
.then(response => response.text())
.then((response) => {
  console.log(response); // returns empty string
  return dispatch({
    type: "GET_CALL",
    response: response
  });
})
.catch(error => { console.log('request failed', error); });

and with .json():

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
})
.then(response => response.json())
.then((response) => {
  console.log(response.body);
  return dispatch({
    type: "GET_CALL",
    response: response.body
  });
})
.catch(error => { console.log('request failed', error); }); // Syntax error: unexpected end of input

Looking in the chrome dev tools:

Answer 1

I just ran into this. As mentioned in this answer, using mode: "no-cors" will give you an opaque response, which doesn't seem to return data in the body.

opaque: Response for “no-cors” request to cross-origin resource. Severely restricted.

In my case I was using Express. After I installed cors for Express and configured it and removed mode: "no-cors", I was returned a promise. The response data will be in the promise, e.g.

fetch('http://example.com/api/node', {
  // mode: 'no-cors',
  method: 'GET',
  headers: {
    Accept: 'application/json',
  },
},
).then(response => {
  if (response.ok) {
    response.json().then(json => {
      console.log(json);
    });
  }
});