Build time macros

Even though macaron's main aim is to be a compile time CSS-in-JS library, it's sophisticated compiler can be used for purposes other than styling.

It can also be used as a smart compile time macro system where you can execute functions at build time, similar to comptime in zig, or babel-plugin-macros while authoring the macros in the same file, as if they were regular functions.

This can be useful to read config files, doing complex calculations or processing files (for eg. optimizing images without needing a seperate plugin) right inside your application code.

You can wrap your functions at usage site in the macaron$ function and they will act as a macro, be executed at build time and their return value will be inlined in the final bundle.

This can be used to do things like reading file system, using any Node API and even executing requests at build time (like getStaticProps in NextJS), all in a client side project.

Example

import { macaron$ } from '@macaron-css/core';
import { readFileSync } from 'fs';
const files = macaron$(() => readFileSync('file.txt', 'utf8'));

The code above gets compiled into :-

const files = '__CONTENTS_OF_FILE_HERE__';