Extending Create React App with Babel Macros

I have a co-dependent relationship with Create React App. When we’re good, we’re really good. When I have an unmet need — when I want to customize some part of the build process — I do my best to make CRA work. And when it doesn’t, for whatever reason, I eject and fall back to Webpack, Babel, & friends, resentful that CRA has let me down. Recently, though, I discovered that you can customize Babel configuration in a Create React App projects without ejecting.

Last month I was working on some shared React components and ran into this again: I wanted to use Tailwind.css — fine — but I also wanted to include it in the resulting Javascript files as CSS-in-JS​*​. I initially despaired, thinking I’d have to eject the components in order to customize the Babel configuration.

And then I discovered Babel Macros, which — lo and behold — are supported by CRA since 2018!

Babel Macros are exactly what they sound like if you’re familiar with Lisp-y languages: they’re code that generates different code. In other words, they give you a functional interface to Babel’s transpiling capabilities. This allows you to write “normal” Javascript (or Typescript) code that CRA can process, but when that code is executed, it hooks into Babel’s runtime.

For my Tailwind CSS-in-JS it looks like this.

First, I tell Babel (and by extension CRA) that I want to enable macros, by adding macros to the list of plugins in my .babelrc:

   "presets": ["@babel/env", "@babel/react", "@babel/typescript"],
   "plugins": [

Then, when I want to use Tailwind-in-JS, I import the macro and use it to tag a string.

import tw from "@tailwindcssinjs/macro";


// in my react component
return (
      style={tw`font-normal text-sm text-gray-700`}

Note that I’m setting what looks like the Tailwind class list as the style property of my element: that’s because tw is actually a function that utilizes Babel’s macro functionality to map the classes to their underlying CSS properties.

With this small bit of configuration in place, running the CRA build script results in pure Javascript I can use in my downstream projects, including the necessary CSS.

There are other advantages, too: someone reading this code can now “follow their nose” to figure out what’s going on. One of the most persistent problems I’ve encountered when approaching a large codebase is understanding how the source is built: where does a dependency come from? how is the code compiled? where — why!? — does a transformation happen? This component now answers those questions for me: the use of Babel (and the macro) is explicit.

  1. ​*​
    There’s probably another post here: getting shared components to work with external CSS has been a real pain for me.

The Habit

A mentor, Naomi, once told me “it’s more fun to write programs that help you write programs than it is to write programs”. While funny — and true, at least for me — I think what she was getting at is something a little more general: meta-work is a way of distracting ourselves from the real work. Or, more nefariously, meta-work is a way of feeling like we’re accomplishing something when we’re standing still (with respect to our goals).

This has been coming up for me recently around blogging and blogging software. I had a really good blogging habit for a while, and it served me well. Arguably I have my career because of it. Today when I read something interesting and want to comment, amplify, or rebut part of it, my thoughts still go to publishing. But I’ve lost the habit, the muscle, so instead I dither. I focus on how much I pay for WordPress hosting​*​. I view-source and look for tell-tale signs of what tool another author is using. I familiarize myself with headless CMSes, flat files, and “IndieWeb” standards. What I do not do is write.

Almost inevitably two things happen. First, I run out of time: I have to get back to work, I have to make dinner, etc. And second, when I finally return to the open browser tabs — now 90% meta, 10% what I wanted to reflect on — I say to myself, “why the fuck not wordpress? it’s not like it’s done anything to you in the past; yeah, it’s not new, and it’s not written in a language you’re enamoured with today, but it’s not like you have time to hack on it anyway. And if you did, you could do a lot worse than plugging into an ecosystem that big. Suck it up.” And then I close the tabs because I’m annoyed with how much time I’ve plowed into not-writing.

Later me is right: writing my own blogging software is in no way a good use of my time right now; I am not not-writing because of the software; using Jekyll Hugo Pelican Plume will not suddenly cause me to blog; making POSSE work is not a way to rebuild the blogging muscle; my theme is not my problem; post formats do not matter; Guttenberg didn’t reduce my likelihood to post; the list goes on.

Sometimes meta work is an interesting, high leverage way to approach things: there have been times I wrote a program that helped me write a program, and the result was doing something in a few days that we thought would take a few weeks​†​. The difference is, in those cases, I was already actively using the mental muscles I needed, I was already in “the habit”. When it comes to writing, making art, or sewing, the habit is really all that matters.

  1. ​*​
    I pay because a few years ago I was trying to get myself out of a similar rut, this time around what VPS to use and how to secure it. That time I told myself, “it doesn’t fucking matter, just pay to have someone else deal with this, and find a managed service.” And I’ve resented them ever since, despite the great service they provide. Probably because I’m not using the service I pay for.
  2. ​†​
    For example, the time I wrote a codemod using jscodeshift that added sane security defaults to Lob’s entire API codebase.

If you want to succeed as an artist, make as much work as possible. That is the secret sauce. Regardless of whether you are after commercial success or simply want to improve in your craft, the answer is the same, make more work.

How To Become A Successful Artist