http request window.fetch() snippet with application/json headers

http-request-fetch.js

fetch('http://HOST/api',
{
  method: 'post', // 'put' 
  headers: { 'Accept': 'application/json, text/plain', 'Content-Type': 'application/json' },
  body: JSON.stringify( {"User_employee_id":"1","template_id":0,"data":[{"id":1509003681672,"contract":"EuroDollar@SEP18"}]} ),
  // cache: 'no-cache', // *default, no-cache, reload, force-cache, only-if-cached
  // credentials: 'same-origin', // include, same-origin, *omit
  // mode: 'cors', // no-cors, cors, *same-origin
  // redirect: 'follow', // manual, *follow, error
  // referrer: 'no-referrer', // *client, no-referrer
})
.then(response => response.json())
.then(console.log)
.catch(console.warn);