nbl/src/http/http.ts

function httpreq(type:string,baseURL:string) {
    return new Promise( (resolve, reject) => {
              // The promise is now in the 'Pending' state
              const xhr = new XMLHttpRequest();
              xhr.open(type, baseURL);
              xhr.send()
              xhr.onreadystatechange = () => {
                if (xhr.readyState < 4) {
                  // The XHR request hasn't completed yet, so I'm just going to return here.
                  return;
                }
            
                if (xhr.status !== 200) {
                  // The Status code of the request is NOT 200, so it must have failed in some way. Reject the promise
                  reject(xhr.response);
                  // After calling reject(), the Promise enters 'rejected' state.
                }
                if (xhr.readyState === 4) {
                  // The readyState of the request is '4', which means its done.
                  // Parse the response into JSON format and resolve the promise
                  resolve(JSON.parse(xhr.response));
                  // After calling resolve(), the Promise enters 'resolved' or 'fulfilled' state.
                }
              }
            
            }); 
}
        
export default httpreq;