Tag Archives: jQuery

The magic JS console thing

Source here – https://github.com/devdave/DevDave-s-miscellanious-bucket/tree/master/jsConsole

Just wanted to see what would be involved in making a terminal like UI for the web. Honestly there’s a few REALLY annoying bits, but with a bit of hackery it was pretty straight forward. I’ve found splitting up the keyCode/which between key press and key down events was a lot simpler then making some sort of jury rigged code to character map when trying to compute shifted keys.

Also, I put in a brutally ugly left to right parser that does auto-complete / tab completion for good measure. It’s got a very limited vocabulary but I could easily snap it into an asyncronous Ajax handler to bridge it with a much more powerful server side module.

Like all of my short term projects, no warranty or guarantee that it works is provided or implied.

Deferreds for JQuery 1.5

Anyone familiar with async programming like Node.JS or Python’s twistd library will be familiar with deferreds. Its usually a simple nuisance to re-implement when needed, so it’s nice to hear that’s not an issue anymore with JQuery’s $.when & $.then methods

Really useful guide here

What does this mean?

Say you’ve got a compound action you want to complete. For example a user clicks on a leaf in a tree like directory
menu. Now you want to update both the menu to add any possible sub nodes of that leaf PLUS update a content panel and once its finished, maybe update the hash tag to the current page’s url.

 
  $.when( updateMenu(), updateContent() )
     .success( function(){
           console.log("Both menu & content panel have been updated!");
      })
     .fail( function(){
           console.log("Oh noes, we didn't finish... try again?");
      });

That’s pretty much the gist of deferreds in a nutshell. Furthermore it appears that the author of this fantastic addition to jQuery really grokked the concept of deferreds because you can chain one deferred result to multiple child deferred’s allowing for cascading events to fire in response to one event.