Rollup config for an Open and Unintrusive Web

unintrusive-ts-rollup.config.js

// This Rollup config file intend to compile each TypeScript file of
// a source folder without too much modification.
// Goal is to make the resulting code easy to read for beginner, debuggers or curious persons
// wanting to see the full source code.
//
// Typescript targets esnext and doesn't changes too much the resulting files
// Modules are resolved including node_modules compiled into ES Modules
// Original source files are copied to output directory
// Header are added to generated files to hint a visitor about the original file
//
// We got the full power of npm, Typescript and all other Rollups plugins
// Without too much obfucation on the resulting files

import resolve from "@rollup/plugin-node-resolve";
import commonjs from "@rollup/plugin-commonjs";
import { fileURLToPath } from "node:url";
import typescript from "@rollup/plugin-typescript";
import json from "@rollup/plugin-json"
import copy from "rollup-plugin-copy";
import nodePolyfills from "rollup-plugin-node-polyfills"
import {glob} from "glob";
import { resolve as pathResolve } from "node:path";
import * as os from "node:os"

// Set folder where uncompiled source are located
let sourceFolder = fileURLToPath(new URL("./src/", import.meta.url));

let copyFolder = `${sourceFolder}/*`
if(os.platform() == "win32") {
    copyFolder = copyFolder.replace(/\\/g, "/");
}

// Extract all typescript files
let sources_files = Object.fromEntries(
  glob
    .sync(`${sourceFolder}/**/*.ts`)
    .map((it) => [pathResolve(it).replace(sourceFolder, "").replace(/\.[^.]+$/, ""), it])
);

export default {
  input: sources_files,

  output: {
    banner: getHeader,
    format: "es",
    dir: "out",
    manualChunks: file_chunking,
    chunkFileNames: "[name].js",
  },

  plugins: [
    // Copy all sources into the public directory
    copy({
      targets: [{ src: copyFolder, dest: "out" }],
    }),
    // Resolve npm modules
    resolve({browser: true, preferBuiltins: false}),
    // Handle non ESM modules
    commonjs(),
    nodePolyfills(),
    json(),
    // Compile typescript
    typescript({
      allowSyntheticDefaultImports: true,
      compilerOptions: {
        lib: ["es5", "es6", "dom", "esnext"],
        target: "esnext",
      },
    }),
  ],
};

// Force code chunking for each file
function file_chunking(id) {
  if (id.includes("node_modules")) {
    return id
      .replace(/^.+\/node_modules\//, "lib/vendor/")
      .replace(/([^.])\.[^.]+$/, "$1");
  } else if (id.startsWith(sourceFolder)) {
    let name = id.replace(sourceFolder, "").replace(/([^.])\.[^.]+$/, "$1");
    if (id.endsWith(".js")) {
      name += ".bundle";
    }
    return name;
  }
}

// Generate a header pointing to the original file (only for file inside source folder)
function getHeader(chunk) {
  let files = Object.keys(chunk.modules)
    .filter((it) => !it.startsWith("\x00"))
    .filter((it) => it.startsWith(sourceFolder))
    .map((it) => it.replace(sourceFolder, ""));

  if (files.length > 1) {
    return `// This file was generated using Rollup from the following files :
${files.map((it) => `// * ${it}`)}
// 
// Take a look at these files to get the original source code
`;
  } else if (files.length == 1) {
    return `// This file was generated using Rollup from "${files[0]}"
// Take a look this file to see the original source code
`;
  }
}

z_install-dependencies.sh

npm install --save-dev rollup @rollup/plugin-node-resolve @rollup/plugin-commonjs @rollup/plugin-typescript @rollup/plugin-json rollup-plugin-copy rollup-plugin-node-polyfills glob tslib