http-helper.js

function http(url, method, payload, callback) {
  const options = {
    method: method ? method : 'GET',
    headers: {
      "Content-Type": "application/json"
    }
  };

  if(payload) {
		options.body = JSON.stringify(payload);
  }
 
  fetch(url, options)
    .then(res => res.json())
    .then(data => {
      if (callback) callback(data);
      else console.log(data);
    })
    .catch(error => console.error(error));
}