Starting point for promise for article on http://theopensourceu.org/concepts-to-implementations-promise/

tOSU-callback-hell.js

// require statements omitted for readability and brevity.
function processData( startingData, cbResult ) {
  //
  // Do something with startingData and ultimatly set result to finalizedResult.
  // ...
  var finalizedResult = startingData;
  cbResult(finalizedResult);
} 

function parentMethod() {
  fs.readFile('/my/made/up/file.txt', function callback1(err, data) {
    if(err) throw err;
    processData( data, function callback2(results) {
      sendResultToServer(result, function callback3(response) {
        executionOrderGetsConfusing(response);
      });
    });
  });
}