How do I avoid deeply nested code in node.js?

Question

In node.js, it being event-driven, all I/O is done via callbacks. So I end up writing code that looks like this:

app.get(\'/test\', function (req, res) {
  ht         


        

Answer 1

Don't use anonymous functions.

EDIT

Your code isn't even valid. You aren't closing most of your function calls.

If you switched to named functions it would look something like this: Updated to reflected comment about global namespace

(function () {
    app.get('/test', f0)

    function f0(req, res) {
      http.get('some/place', f1)
    }

    function f1(req1, res1) {
        if (res1.statusCode == 200) {
          res1.on('data', f2)
        }
     }
    function f2(data) {
        http.get('other/place?q=' + data, f3)
    }
    function f3(req2, res2) {
      if (res2.statusCode == 200) {
        res2.on('data', f4)
      }
    }

    function f4(data) {
          db.query(data).on('data', f5)
        }

    function f5(rows) {
        res.writeHead(200)
        res.end(JSON.stringify(rows))
    }
})()