build.js

import { readdir, rm, mkdir, rename } from 'node:fs/promises';
import { join, resolve } from 'path';

const start = performance.now();
const srcDir = join('src', 'main', 'resources', '_static');
const targetDir = join('target', 'classes', '_static');

async function fileHash(file) {
    const md5Hasher = new Bun.CryptoHasher('md5');
    return md5Hasher.update(await file.text()).digest('hex').substring(0, 16);
}

async function deleteExistingOutput() {
    await Promise.all(['styles', 'js'].map(async resource => {
        const folder = join(targetDir, resource);
        await rm(folder, { recursive: true });
        await mkdir(folder);
    }));
}

async function exportTailwind() {
    const tailwindInput = join(srcDir, 'styles', 'style.css');
    const tailwindOutput = join(targetDir, 'styles', `style.min.css`);
    const exitCode = await Bun.spawn([join('node_modules', 'bun', 'bin', 'bun'), 'tailwindcss', '-i', tailwindInput, '-o', tailwindOutput, '--minify'], {stdio: ['inherit', 'ignore', 'ignore']}).exited;
    if (exitCode !== 0) console.error("TailwindCSS bundling failed with exit code ", exitCode);
    await rename(tailwindOutput, join(targetDir, 'styles', `style--${await fileHash(Bun.file(tailwindOutput))}.min.css`));
    return exitCode === 0;
}

async function exportBundles() {
    const plugins = [
        {
            name: 'export-css',
            setup: (build) => {
                build.onLoad({filter: /\.css$/}, async ({path}) => {
                    const fileName = path.replace(/.*\//, '').replace(/(--.*)?\..+$/, '');
                    const inputFile = Bun.file(path);
                    const outputName = `${fileName}--${await fileHash(inputFile)}.min.css`;
                    const outputFile = Bun.file(join(targetDir, 'styles', outputName));
                    await Bun.write(outputFile, inputFile);
                    return { contents: `window.requires('/_static/styles/${outputName}');`, loader: 'js' }
                });
            }
        },
        {
            name: 'inject-local',
            setup: (build) => {
                build.onResolve({filter: /local_modules/}, async ({path}) => {
                    const newPath = join(resolve(), path);
                    return { path: newPath,  loader: 'js' };
                });
            }
        }
    ];
    const jsPath = join(srcDir, 'js');
    const build = await Bun.build({
        entrypoints: (await readdir(jsPath)).map(fn => join(jsPath, fn)),
        outdir: join(targetDir, 'js'),
        minify: {
            whitespace: true,
            identifiers: true,
            syntax: true,
        },
        sourcemap: 'external',
        target: 'browser',
        naming: '[name]--[hash].min.[ext]',
        plugins: plugins
    });
    if (!build.success) console.error("Bun build failed with the following logs: ", build.logs);
    return build.success;
}

await deleteExistingOutput();
const result = await Promise.all([exportTailwind(), exportBundles()]);
if (result.includes(false)) console.error("Resource bundling failed, see console for details");
else console.log(`Resource bundling completed in ${Math.round(performance.now() - start)}ms`);