Promise.series

promise-series.js

//Run an array of values in series.
//Non-functions are wrapped in Promise.resolve().
//Functions are passed to the Promise constructor. (eg new Promise(myFunction);)
//Series order starts from 0.
Promise.series = function PromiseSeries(promises) {
  function assignTo(o, k) {
    return function(v) {
      o[k] = v;
      return v;
    };
  }
  function interator(v, i, arr, varr, gr, gx) {
    if(i == arr.length)
      return gr(varr);
    var p;
    if(typeof v == 'function') {
      p = (new Promise(v));
    } else {
      p = Promise.resolve(v);
    }

    p
      .then(assignTo(varr, i))
      .then(interator.bind(this, arr[i+1], i+1, arr, varr, gr, gx))
      .catch(gx);
  };

  return new Promise(function(resolve, reject) {
    var si = promises.length-1;
    var varr = new Array(promises.length);
    interator(promises[0], 0, promises, varr, resolve, reject);
  });
};

//
//  Example
//
var series = [1,2,3, function(resolve, reject) { setTimeout(resolve.bind(null, 1337), 5000); }, [Promise.resolve(5)]];
Promise.series(series).then(console.log);
> [1, 2, 3, 1337, [Promise]]