fetch content with timeout

fetch.js

const MIN_LOADING_TIME = 4000;

function fetchContent (url, options) {
  // fetch from remote or get from cache
  return fetch(url, options).then(response => response.json())
}

function wait(time) {
  return new Promise(resolve => setTimeout(resolve, time))
}

function load(url, options) {
  return Promise.all([
    fetchContent(url, options),
    wait(MIN_LOADING_TIME)
  ])
  .then((...args) => args[0])
  .then(
    data => {
//       someCustomSuccessCallback(data);
      return data;
    },
    err => {
//       someCustomErrorCallback(err);
      return err;
    }
  );
}


//USAGE
const start = +new Date;

// load info about current gist
load('https://api.github.com/gists/b13692cd7bf44e16bba04945eda3da29')
  .then(data => console.log(data))
  .then(() => {
    console.log(`Should be no less than ${MIN_LOADING_TIME}: ${+new Date - start}`);
  });