Tricky regex: Allow only first occurence of a character

[creole]

I've got a tricky piece of regex I need help with.

I have a string(s):
used inventory/ford/focus/lx
used-inventory/ford/focus
aboutus/ourteam/andy matthews

All of which need to have non alpha-numeric characters removed (barring dashes, and ONE slash, the first one). Given that, the above strings would need to be converted to:

used-inventory/ford-focus-lx
used-inventory/ford-focus
aboutus/ourteam-andy-matthews

The JS I'm using atm:

var regex = /[^a-zA-Z0-9/-]/gi;
var str = 'used inventory/ford/ding/dong';
var final = str.replace(regex,'-');
console.log(final);

Can anyone help out?

[JimmyP]

This should work:

theString.replace(/[^\w]/g, function(m){
    if ( m === '/' && !arguments.callee.firstSlash ) {
        arguments.callee.firstSlash = true;
        return m;
    }
    return '-';
});

When the first slash is encountered the Boolean 'firstSlash' property of the function is changed to true, meaning that only the very first slash will be allowed, all others will be treated like regular non-alphanumeric characters (replaced with '-').

[creole]

Whoa...had no idea the replace method took a callback function! I'll give this a shot JimmyP, thanks a lot!

[creole]

Err...not callback, but function as argument.

[creole]

Worked perfectly! This is what I've got:

var regex = /([^a-zA-Z0-9-])/gi;
var str = 'used/inventory/ford/focus/lx';
var final = str.replace(regex, function(m){
	if ( m === '/' && !arguments.callee.firstSlash ) {
		arguments.callee.firstSlash = true;
		return m;
	}
	return '-';
});
console.log('src: '  + str);
console.log('final '  + final);