Pre-Compile JavaScript from VS2008 IDE

Question

Is there a way for me to pre-compile my JS code when building my solution? I would like to be made aware of common problems before I get to the browser. Ideally I would build the sln and, if necessary, have a plugin or call from the build events examine the js code against a Java compiler. Thank you very much in advance!

Answer 1

Javascript is an interpreted language, it's not compiled till runtime. Also, javascript has very, very little to do with Java. Netscape released JavaScript around the same time Sun released Java, and there was some sort of marketing deal between them. Otherwise, they're unrelated.

Answer 2

Javascript isn't compiled, has nothing to do with Java but some shared syntax, and is best tested by loading your app into a browser.

There are some JS testing frameworks/tools available but I couldn't recommend any of them myself.

Answer 3

Despite what many of the other posters have said, in many cases (incl. the Mozilla Spidermonkey engine found in the Firefox browser) Javascript is in fact compiled into bytecodes, vaguely similar to (but not compatible with) the ones used in Java. You just don't see the compiler's output because it is never available to you, only to the Javascript bytecode interpreter. It's also not possible to save the compiled bytecodes for reuse (at least in the web browser context; in alternate uses of the Spidermonkey engine I do think it is possible to save the compiled bytecodes in memory for reuse, but not in a form that can be saved to disk for another future use), as far as I know.

I use a Javascript shell JSDB which also uses the Spidermonkey engine; when you load in a file, it will complain about syntax errors before it runs even one line of code. This is not the same type of compilation as Java, though; Javascript is a loosely-typed language and so it won't catch problems the way a Java compiler would (e.g. complain about every last thing under the sun that it knows you haven't done right).

Having said that, I would second JSLint as it would probably catch many of your errors.

As a side note, the Rhino project lets you compile Javascript into Java classes; i've never tried this but it sounds interesting.

Answer 4

I apologize for my misuse of the term 'compile'. I do fully understand the difference between compiled and interpreted languages. What I am interested in is to have my syntax checked routinely during a build so typos, invalid method calls and the like are flagged. I'm going to look into what Jason S recommended for this. I am also fully aware that JavaScript is not Java, but have read before that you could run your JS code through a Java Compiler for syntax checking. I was hoping to find something better integrated with VS.
Thank you very much to everyone understanding the intent of my request.