Fiber() is under the hood, and I hope ES6 generators -when stable- will provide similar tools, so wait.for could be based on ES6 generators.

You don't have to wrap all your code in a call to `Fiber()`

full classic node-server sample:

    var http=require('http'), wait=require('wait.for');

    http.createServer(function(req, res) {
      wait.launchFiber(handleRequest,req, res); //run in a Fiber, keep node spinning
    }).listen(8080);


   //in a fiber
   function handleRequest(req, res) {
     try {
       res.writeHead(200, {'Content-Type': 'text/html'});
       res.end(
       "<h1>Demo page</h1>" 
       + "<p>"+ wait.for(fs.readFile,'/etc/somefile') +"</p>"
       + "<p>"+ wait.for(fs.readFile,'/etc/otherfile') +"</p>");
     }
     catch(err) {
      res.end('error '+e.message); 
     }
   }

in your example below, you do have to wrap it in a call to `Fiber()`, although you've disguised it as `launchFiber`, which you pass `handleRequest` to (I would call that wrapping `handleRequest`.

That is probably a worthwhile tradeoff, but the first time I read through it, that mechanic wasn't obvious to me.

It's not 'disguised', it's abstracted. launchFiber does what it's name implies: launchs a fiber. How it is achieved 'internally', it's irrelevant as long the abstraction is not leaky.

Today launchFiber is calling the fn inside a Fiber(), tomorrow could be launching the fiber by means of a generator.

The idea was to create a very simple abstraction to avoid callback hell, adding low or no complexity, and keeping the flexibility to use all the existing async fns with a callback or just "wait" for the results.