Example of Bluebird's Promise.coroutine

promise_coroutine.js

var Promise = require('bluebird');
var request = require('request');
var fs = require('fs');

request_promise = Promise.promisify(request);
writeFile_promise = Promise.promisify(fs.writeFile);

Promise.coroutine(function* () {
	try {

		//I think this is way more readable:
		var response = yield request_promise('https://s3.amazonaws.com/aaronblondeau/widgets/widgets.json');
		var data = JSON.parse(response.body);
		yield writeFile_promise('./widgets.json', JSON.stringify(data.widgets));
		console.log("Done.");

	}
	catch(err) {
		// Hey - cool a real live try-catch to handle our errors!
		console.error(err);
	}
})();