Thoughts on JavaScript compilers

I think JavaScript compilers sort of defeat the purpose of a programming language. I can understand that you would want to compress JavaScript to save download time on the client side.

However, it seems strange to me that another programming language writes code in another, higher level language. If the JavaScript you write is good and not highly redundant, another PL wont be able to generate it. The only place where it seems useful to me is when creating variables' values like a count or an array of file names or similar. However, generating JavaScript from PHP or any other server side language seems to defeat the purpose of reusable code. You can in fact write highly re-usable code in JavaScript, it supports inheritance etc and libraries like jQuery make it highly compact. When it comes to deployment though, it is beneficial to have a script running that compresses the JavaScript.

Anyway, let me know your thoughts in a comment.

Comments

• Jevon

  What do you mean by "Javascript compiler"? It seems you are mixing a number of terms together. There are Javascript recompilers, which remove unused methods and variables; Javascript reformatters, which remove comments and whitespace; Javascript generators, which take some source (of any language) and generates Javascript; and Javascript compilers, which are compilers written in Javascript (emulators, for example). Remember that not every browser implements Javascript the same. HTML5 Javascript is different to HTML4+Google Gears Javascript, for example. Generating Javascript at server request time allows for a more efficient script to be sent to the server, and you wouldn't have to maintain multiple versions for each platform. Generating Javascript isn't useful for all situations, of course. But it's not useless for all situations, either.

  7/25/2010, 12:47:22 PM

• dcodernz

  By JavaScript compiler I meant something like this: http://pyjs.org/ . And yes, you have a point. Haven't thought about this: "Remember that not every browser implements Javascript the same. HTML5 Javascript is different to HTML4+Google Gears Javascript, for example. Generating Javascript at server request time allows for a more efficient script to be sent to the server, and you wouldn’t have to maintain multiple versions for each platform.". I assume you meant client and not server here.

  7/25/2010, 8:50:42 PM

• dcodernz

  Just had a look again at a particular compiler for OpenLayers. In this case it is very useful because you can declare the classes you need from OpenLayers and it compiles a minified version of it. Compile might be the wrong word here as it is merely minified or built with the help of a python script. You have to declare your classes in a separate file. It would be nice to be able to give it simply another JavaScript file which it examines for classes used, then one woudln't have to do the analysis any more.

  8/6/2010, 6:57:50 AM