promises.js

// Sequence of promises
 
let promise = Q();
let result = [];
R.forEach(page => {
  promise = promise.then(r => {
    result = R.merge(r, result);
    return fetch(page);
  });
}, R.range(0, pages));

return promise.then(() => {
  console.log('result: ', result);
});
        
// Alternative way
var promise = Q();
R.reduce((memo, page) => {
  return memo.then(r1 => {
    return fetch(page)
      .then((r2) => r1.concat(r2))
  });
}, Q.resolve([]), R.range(0, pages));