I have this code below, using the npm.js api request

let inputContent = {
  prompt: req.body.prompt
}

inputContent.prompt = JSON.stringify(inputContent.prompt)
request.post({
  url: 'https://my.api.com/',
  headers : {
    "content-type": "application/json",
  },
  body: { 
    "prompt": inputContent.prompt,
    "max_tokens": 4000
  },
  json: true
}, function(err, httpResponse, body) {
  if (err) {
      console.log(err)
  } else {
      console.log("body response is")
      console.log(body)
  }
})

I expect a response through body, but it keeps returning undefined. I also tried using form instead of body, and i tried removing json. Could anyone offer some advice?