node.js - Why use javascript callbacks when cleaner syntax is available? -

i'm trying learn use node. far, good. but, being pretty new javassript , don't point of using callbacks when cleaner , more readable (at least me) syntax available.

here's example code make point clearer:

with callback:

exports.create = function(req, res){   new todo({     content    : req.body.content,     updated_at : date.now()   }).save(function(err, todo, count){     res.redirect('/');   }); }; 

without callback:

exports.create = function(req, res){   newtodo = new todo({     content    : req.body.content,     updated_at : date.now()   });   newtodo.save();   res.redirect('/'); }; 

both of these codes save new todo , redirect.

my preference goes second one, find easier read, maybe there's difference don't get. there difference?

the short answer is: avoid locking user interface while operation takes time finishing executing.

in second example, if save function makes ajax call, have make synchronous ajax call.