vite.config.ts

import preact from '@preact/preset-vite'
import { ConfigEnv, UserConfig, defineConfig } from "vite";
import fs from 'fs';


export default defineConfig((mode: ConfigEnv): UserConfig => {
  return {
    plugins: [preact()],
    build: {
      target: "esnext",
      minify: false,
      outDir: "dist",
      watch: 'src',
      lib: {
        entry: 'src/index.tsx',
        name: 'index',
        fileName: () => 'index.user.js',
        formats: ["iife"]
      },
      rollupOptions: {
        output: {
          banner: () => fs.readFileSync('src/userscript-header.js', 'utf-8')
        },
      }
    },
    define: {
      // https://github.com/vitejs/vite/discussions/13587
      "process.env.NODE_ENV": JSON.stringify(mode),
  },
  }
});