Javascript string replace with regex to strip off illegal characters

Question

Need a function to strip off a set of illegal character in javascript: |&;$%@"<>()+,

This is a classic problem to be solved with regexes, which means now I have 2 problems.

This is what I've got so far:

var cleanString = dirtyString.replace(/\|&;\$%@"<>\(\)\+,/g, ""); 

I am escaping the regex special chars with a backslash but I am having a hard time trying to understand what's going on.

If I try with single literals in isolation most of them seem to work, but once I put them together in the same regex depending on the order the replace is broken.

i.e. this won't work --> dirtyString.replace(/\|<>/g, ""):

Help appreciated!

Answer 1

What you need are character classes. In that, you've only to worry about the ], \ and - characters (and ^ if you're placing it straight after the beginning of the character class "[" ).

Syntax: [characters] where characters is a list with characters.

Example:

var cleanString = dirtyString.replace(/[|&;$%@"<>()+,]/g, ""); 

Answer 2

I tend to look at it from the inverse perspective which may be what you intended:

What characters do I want to allow?

This is because there could be lots of characters that make in into a string somehow that blow stuff up that you wouldn't expect.

For example this one only allows for letters and numbers removing groups of invalid characters replacing them with a hypen:

"This¢£«±Ÿ÷could&*()\/<>be!@#$%^bad".replace(/([^a-z0-9]+)/gi, '-'); //Result: "This-could-be-bad"