astro/scripts/cmd/build.js

import esbuild from 'esbuild';
import del from 'del';
import { promises as fs } from 'fs';
import { resolve } from 'path';
import glob from 'tiny-glob';

/** @type {import('esbuild').BuildOptions} */
const config = {
    bundle: true,
    minify: true,
    sourcemap: 'inline',
    format: 'esm',
    platform: 'node',
    target: 'node14'
}

export default async function build(pattern, ...args) {
    const isDev = args.pop() === 'IS_DEV';
    const entryPoints = await glob(pattern, { filesOnly: true, absolute: true });
    const { type = 'module', dependencies = {} } = await fs.readFile('./package.json').then(res => JSON.parse(res.toString()));
    const format = type === 'module' ? 'esm' : 'cjs';
    const external = Object.keys(dependencies);
    const outdir = 'dist';
    await clean(outdir);

    if (!isDev) {
        await esbuild.build({
            ...config,
            entryPoints,
            outdir,
            external,
            format
        });
        return;
    }

    const builder = await esbuild.build({
        ...config,
        watch: true,
        entryPoints,
        outdir,
        external,
        format
    });

    process.on('beforeExit', () => {
        builder.stop?.();
    })
    
}

async function clean(outdir) {
    return del(`!${outdir}/**/*.d.ts`);
}