CNAT

Class Name Alteration Tool. Systematically change all the class names in your codebase.

Install

cargo install cnat

npm install -g cnat

Why?

Because you joined a project that has some awful old tailwind configs: weird bespoke spacing configuration, weird sizes, some current tailwind default colors (e.g. slate) not available because the config was for an older version of tailwind, etc...

So now you can't just copy/paste tailwind class names from the internet or use ones that come from a ui component library. Say you want to use shadcn/ui; Nope!

You want to do something about this, but it's way too risky and time consuming. You would want to do this incrementally, to protect your sanity.

The best solution would be to deprecate the old configs while keeping them around and working; so you slap a prefix legacy- in the old tailwind.config.js.

Deprecation Steps

In the root of your project. Run:

npx tailwindcss -i <(echo '@tailwind utilities;') -o legacy-tw.css
cnat prefix -i legacy-tw.css --prefix 'legacy-' .

By default, cnat prefix will crawl through all the class=*, className=* in jsx elements and className:* in a React.createElement calls, inside of ts|js|tsx|jsx files. It will match any class in the source code with classes found in legacy-tw.css (which contains every style that tailwind generates based on your config).

Add the prefix in the legacy config file.

/** @type {import('tailwindcss').Config} */
module.exports = {
  prefix: "legacy-",
};

Then update your global css with the tailwind directives. Create a new file for the old configs, tailwind.legacy.config.js. Then, create an additional css file which the tailwind directives as such:

./legacy-tw.css

@config "./tailwind.legacy.config.js";
@tailwind base;
@tailwind components;
@tailwind utilities;

@config requires tailwind v3.2 btw.

Import that css file in where-ever the entry point for your project is. For example in Nextjs, you can add it to the _app.tsx file (pages directory version).

import "./legacy-tw.css";

Usage

Systematically apply certain modifications to classes, class names, used in your frontend codebase.

Usage: cnat <COMMAND>

Commands:
  prefix      Apply a prefix to all the tailwind classes in every js file in a project
  completion  Generate completions for a specified shell
  help        Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

cnat prefix --help

Apply a prefix to all the tailwind classes in every js file in a project

Usage: cnat prefix [OPTIONS] -i <CSS_FILE> --prefix <PREFIX> <CONTEXT>

Arguments:
  <CONTEXT>  The root directory of the js/ts project

Options:
  -i <CSS_FILE>             The output css file generated by calling `npx tailwindcss -i input.css -o output.css`
  -p, --prefix <PREFIX>     The prefix to apply to all the tailwind class names found
  -s, --scopes <SCOPES>...  Define scope within which prefixing happens. Example: --scopes 'att:className,*ClassName prop:classes fn:cva' [default: "att:class,className fn:createElement"]
  -h, --help                Print help