Using Preact in production with Rails' Webpacker

Preact is like React but smaller in size. I think? Anyway, so I’ve been told. It’s also different in some ways and I’m not entirely sure how, but they have this thing called preact-compat that’ll plug right into your Webpack config and use Preact instead of React which seems like free filesize savings. Right on!

First:

$ yarn add preact-compat webpack-merge

In config/webpack/production.js:

const environment = require("./environment");
const merge = require("webpack-merge");

module.exports = merge(environment.toWebpackConfig(), {
  resolve: {
    alias: {
      react: "preact-compat",
      "react-dom": "preact-compat",
    },
  },
});

I saved 2 whole megabytes with just this change. No, of course that’s not true.