javascript - Remove all ANSI colors/styles from strings

Question

I use a library that adds ANSI colors / styles to strings. For example:

> "Hello World".rgb(255, 255, 255)
'u001b[38;5;231mHello Worldu001b[0m'
> "Hello World".rgb(255, 255, 255).bold()
'u001b[1mu001b[38;5;231mHello Worldu001b[0mu001b[22m'

When I do:

console.log('u001b[1mu001b[38;5;231mHello Worldu001b[0mu001b[22m')

a "Hello World" white and bold message will be output.

Having a string like 'u001b[1mu001b[38;5;231mHello Worldu001b[0mu001b[22m' how can these elements be removed?

foo('u001b[1mu001b[38;5;231mHello Worldu001b[0mu001b[22m') //=> "Hello World"

Maybe a good regular expression? Or is there any built-in feature?

---

The work around I was thinking was to create child process:

require("child_process")
 .exec("node -pe "console.error('u001b[1mu001b[38;5;231mHello Worldu001b[0mu001b[22m')""
 , function (err, stderr, stdout) { console.log(stdout);
 });

But the output is the same...

Answer 1

The regex you should be using is

/[u001bu009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g

This matches most of the ANSI escape codes, beyond just colors, including the extended VT100 codes, archaic/proprietary printer codes, etc.

Note that the u001b in the above regex may not work for your particular library (even though it should); check out my answer to a similar question regarding acceptable escape characters if it doesn't.

If you don't like regexes, you can always use the strip-ansi package.

---

For instance, the string jumpUpAndRed below contains ANSI codes for jumping to the previous line, writing some red text, and then going back to the beginning of the next line - of which require suffixes other than m.

var jumpUpAndRed = "x1b[Fx1b[31;1mHello, there!x1b[mx1b[E";
var justText = jumpUpAndRed.replace(
    /[u001bu009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g, '');
console.log(justText);