Javascript comment stripper

Question

I'm looking for some tool to remove cooments from Javascript sources. I was able to Google some, but none of them satisfied the following requirement: Everything else should be left as it is, in particular white space is not removed, BUT if a comment takes a whole line, the line is removed too.

Shortly, I want to be able to go from a nicely formatted source with comments to an equally formatted source without comments. Lines which only contain comments are removed, and traliing comments are removed together with the trailing spaces. All the rest is left as it is.

Do you know any tool for such a job?

EDIT: I try to be more specific. Using regular expressions is not possible, as the characters // or /* can also appear inside strings, regular expressions and so on.

The tool should take this input

var a = true;

//the following code is every useful
var b = 2;//really, really useful
 /**
Never, ever do this
var c = 3;
  */
var d = 4;

and give this output

var a = true;

var b = 2;
var d = 4;

Answer 1

Just do a regular expression find and replace.

1. Regex starting with //, containing all symbols and whitespace, and ending with line break
2. Regex starting with /*, containing all symbols, whitespace, and breaks, and ending with */

Answer 2

Here's some code I whipped up: http://trinithis.awardspace.com/commentStripper/stripper.html

Here's one I didn't write that could be handy, though his code will fail on certain regex literals: http://james.padolsey.com/javascript/removing-comments-in-javascript/

Answer 3

Use Google's Closure Compiler with WHITE_SPACE_ONLY and PRETTY_PRINT -- the only thing that it will do is remove the comments (Unless of course you don't format your code in the way that PRETTY_PRINT does.)

It turns this:

// This function alerts a name
function hello(name) {
    /**
    * One lone
    * multi-line
    * comment
    */
    alert('Hello, ' + name);
}
hello('New user');

Into this:

function hello(name) {
  alert("Hello, " + name)
}
hello("New user");