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All the examples, github repos, books, and tutorials I'm seeing with my dive into node say exactly the opposite - the code becomes a mess of callbacks. It looks

by bphogan 15y ago

All the examples, github repos, books, and tutorials I'm seeing with my dive into node say exactly the opposite - the code becomes a mess of callbacks. It looks like enormous work goes into avoiding callbacks, similar to the amount of work that went into Rails in 2005 so that server-side folks could avoid writing JavaScript. I'd love to see this framework you wrote. Is it open-source? or is it something you're unable to share?

MatthewPhillips 15y ago
You have to think about async code differently than you think about synchronous code. In PHP you might write: $data = getData(); And people want to substitute the return for a callback in js. getData(function(data) { // Do something with data. }); That indeed does lead to callback mess. But when you are coding in js you rarely should use anonymous functions. I mostly just use them when I might want to perform recursion. Going back to my example, I would write the operation as an object like so: var SomeObject = { start: function() { getData(dataGot); }, dataGot: function(data) { } }; JavaScript is an object-oriented languages; use objects! They make async painless.
- tomp 15y ago
  > JavaScript is an object-oriented languages; use objects! They make async painless. In the example above, you're unable to use ''this'' in the ''dataGot'' function (when invoked as a callback). Object orientedness is very easy to get wrong in JavaScript, if you're coming from C++/Java/Python background.
  - MatthewPhillips 15y ago
    Right, I excluded the bind for the sake of simplicity. I also forgot that it's this.dataGot. dataGot doesn't exist in that context :)
- bphogan 15y ago
  Wrapping things in objects doesn't seem to help me. I'd still end up with this, thanks to callbacks. app.get('/documents', function(req, res) { Document.find().all(function(documents) { // 'documents' will contain all of the documents returned by the query res.send(documents.map(function(d) { // Return a useful representation of the object that res.send() can send as JSON return d.__doc; })); }); }); Seems to me that what's missing is something that lets me write it in a more simple way. What I have here looks like an absolute nightmare of coupling. So if you have some suggestions you could point me to that show a little more detail, I'd be really grateful.
  - MatthewPhillips 15y ago
    I would create a DocumentRequest object that takes your req and res, then break apart your callbacks to separate functions on the DocumentRequest prototype. Then you would simply consume it with: app.get('/documents', new DocumentRequest);
    - bphogan 15y ago
      Thanks for this. Been thinking about this. Could you recommend a book on patterns like these?

by bphogan 15y ago

MatthewPhillips 15y ago

You have to think about async code differently than you think about synchronous code. In PHP you might write: $data = getData(); And people want to substitute the return for a callback in js. getData(function(data) { // Do something with data. }); That indeed does lead to callback mess. But when you are coding in js you rarely should use anonymous functions. I mostly just use them when I might want to perform recursion. Going back to my example, I would write the operation as an object like so: var SomeObject = { start: function() { getData(dataGot); }, dataGot: function(data) { } }; JavaScript is an object-oriented languages; use objects! They make async painless.

tomp 15y ago
> JavaScript is an object-oriented languages; use objects! They make async painless. In the example above, you're unable to use ''this'' in the ''dataGot'' function (when invoked as a callback). Object orientedness is very easy to get wrong in JavaScript, if you're coming from C++/Java/Python background.
- MatthewPhillips 15y ago
  Right, I excluded the bind for the sake of simplicity. I also forgot that it's this.dataGot. dataGot doesn't exist in that context :)
bphogan 15y ago
Wrapping things in objects doesn't seem to help me. I'd still end up with this, thanks to callbacks. app.get('/documents', function(req, res) { Document.find().all(function(documents) { // 'documents' will contain all of the documents returned by the query res.send(documents.map(function(d) { // Return a useful representation of the object that res.send() can send as JSON return d.__doc; })); }); }); Seems to me that what's missing is something that lets me write it in a more simple way. What I have here looks like an absolute nightmare of coupling. So if you have some suggestions you could point me to that show a little more detail, I'd be really grateful.
- MatthewPhillips 15y ago
  I would create a DocumentRequest object that takes your req and res, then break apart your callbacks to separate functions on the DocumentRequest prototype. Then you would simply consume it with: app.get('/documents', new DocumentRequest);
  - bphogan 15y ago
    Thanks for this. Been thinking about this. Could you recommend a book on patterns like these?