Coroutines example

express-coroutine.js

var Promise = require('bluebird');

module.exports = function wrap(genFn) {
  const promisedFunc = Promise.coroutine(genFn);

  return (req, res, next) => {
    promisedFunc(req, res, next).catch(next);
  }
};


// ------------------------------------------------------

var express = require('express');
var router = express.Router();

router.get('/items/:id', [ wrap(getItem) ]);

// Express error handling
router.use(function(err, req, res, next){
  if(!err) return res.send('');
  res.status(500).send({error: err.message || err});
});

// Coroutine - handler
function* getItem(req, res){
  const data = yield fetch('http://url/item.txt');
  if(!data) return res.status(404).send('not found');
  res.send(data);
}