How do I read a form-data response body in Node?

Question

I do a post to https://api.instagram.com but I don't know how to read the response. When I try console.log(response.body); I get undefined

Here is my code:

var form = new FormData();
  form.append('client_id','fc50049ba7df49b7b96535f892642366')
  form.append('client_secret','6658e18d25e740e691c0cdcdd9adeabf')
  form.append('grant_type','authorization_code')
  form.append('redirect_uri','http://localhost:1992/oauth/ig')
  form.append('code',req.query.code)
  form.submit("https://api.instagram.com/oauth/access_token", (error, response) => {
    console.log(`STATUS: ${response.statusCode}`);
    console.log(`HEADERS: ${JSON.stringify(response.headers)}`);
    console.log(response.body)
    var body = "";
    response.setEncoding('utf8');
    response.on('data', function(chunk) {
        body += chunk;
    });
    response.on('end', function() {
        console.log(body);
        res.send(body);
    });
  });

Answer 1

The response type from form.submit() is IncomingMessage, from http. So you can do this:

res.on('data', (chunk) => {
    console.log(chunk) // this is your response body
})

Answer 2

If you want to get a string you must do an toString:

res.on('data', (chunk) => {
  console.log(chunk.toString()) // this is your response body
})