timeout promise use with window.fetch

timeoutPromise.js

// ref: https://github.com/github/fetch/issues/175
function timeoutPromise(ms, promise) {
  return new Promise( (resolve, reject) => {
    const timeoutId = setTimeout( () => {
      reject( new Error("timeout") )
    });

    promise.then(
      (res) => {
        clearTimeout(timeoutId);
        resolve(res);
      },
      (err) => {
        clearTimeout(timeoutId);
        reject(err);
      }
    )
  })
}