Are there any mand-line Linux tools that can catch basic syntax errors and pile time errors in my Javascript files, even if said Javascript files are written for use in a web browser?
I typically code my Javascript at the same time I'm coding my server side code in say Ruby or Perl. It would save me significant time if I could partially test my client side Javascript the same way I test my server side Ruby and Perl -- on the mand line, typically from within emacs. I'm not expecting to catch run time JavaScript errors on the server, just basic things like a mistyped variable name or an extra bracket somewhere or a runaway string, things that could be found before actually attempting to execute the code.
What I do now to test/debug Javascript is the usual cycle of "visit web app in browser; check Firebug or other console; back to emacs to fix errors; repeat." Doing that is certainly unavoidable for more plex types of errors (e.g. involving user and network interaction) but a garden variety syntax error could be caught and dealt with more quickly on the mand line without loading up the browser.
I've looked a bit into some server side platforms like node.js, but they all seemed geared toward writing and executing server side code (so all of the client side specific bits in my code would presumably make it barf). I also found an emacs mode for javascript REPL but it doesn't seemed designed to do just basic pile checks - it basically loads the whole page via an external graphical browser and lets you monkey with it, which is precisely what I'm trying to avoid.
Are there any mand-line Linux tools that can catch basic syntax errors and pile time errors in my Javascript files, even if said Javascript files are written for use in a web browser?
I typically code my Javascript at the same time I'm coding my server side code in say Ruby or Perl. It would save me significant time if I could partially test my client side Javascript the same way I test my server side Ruby and Perl -- on the mand line, typically from within emacs. I'm not expecting to catch run time JavaScript errors on the server, just basic things like a mistyped variable name or an extra bracket somewhere or a runaway string, things that could be found before actually attempting to execute the code.
What I do now to test/debug Javascript is the usual cycle of "visit web app in browser; check Firebug or other console; back to emacs to fix errors; repeat." Doing that is certainly unavoidable for more plex types of errors (e.g. involving user and network interaction) but a garden variety syntax error could be caught and dealt with more quickly on the mand line without loading up the browser.
I've looked a bit into some server side platforms like node.js, but they all seemed geared toward writing and executing server side code (so all of the client side specific bits in my code would presumably make it barf). I also found an emacs mode for javascript REPL but it doesn't seemed designed to do just basic pile checks - it basically loads the whole page via an external graphical browser and lets you monkey with it, which is precisely what I'm trying to avoid.
Share Improve this question edited Oct 24, 2013 at 18:50 Eric Leschinski 154k96 gold badges422 silver badges337 bronze badges asked Dec 4, 2010 at 21:40 Ryan TateRyan Tate 1,6032 gold badges16 silver badges21 bronze badges5 Answers
Reset to default 1Things like YUICompressor effectively do a syntax check too.
This isn't a direct answer to your question as it is a GUI tool, but I'm a big fan of Aptana. It uses SpiderMonkey to pile your code in the background and give you red squigglies for syntax errors as you type. (It also does the same for HTML.) It also tries to give you intellisense for JS, but it is hit-or-miss. It is nice when it works.
Since I probably haven't convinced you to change your development environment, let's answer your question directly. Why not use the SpiderMonkey engine to throw together a mand-line app that does what you're looking for? It looks easy enough to plug in. You won't even have to worry about the fact that you're guaranteed to get runtime exceptions (there will be no DOM objects in your environment) — you don't have to actually execute the script. Just call JS_CompileScript and check for success. (And then destroy the JSScript object, of course.)
Or, if you're lazy, you could try Rhino Shell, which is a mand-line Java tool which executes JavaScript.
I find JSHint, + its vim plugin are very useful. Light weight of vim and still be able to track the syntax errors of the javascript. JSHint can also be used as a mand line tool.
https://github./walm/jshint.vim
I wrote quick-lint-js for this purpose. It points out syntax errors, among other things.
quick-lint-js integrates with several code editors, such as Vim and Visual Studio Code. It also has a UNIX-style mand-line utility if you prefer.
Javascript debugger with a console in chrome:
The Chrome browser has a javascript debugger can find JavaScript errors:
In Chrome click Tools -> JavaScript Console:
This is examining a JavaScript page with the following code:
var error(){
}
And it tells me what is wrong with it, unexpected '('.
Telling me I can't define a function like that on line 14 of my javascript file.
If you click on the link next to the error, it will take you to and highlight the line that has the error/warning.