[feat] migrate userscript loader to ESM

[loynoir]

feat

migrate userscript loader

from

• assuming legacy global IIFE userscript and dependency

// foo.user.js

@require https://legacy-global-iife-cdn/bar
@require https://legacy-global-iife-cdn/baz

legacy global IIFE

to

• assuming modern ESM userscript and dependency

// foo.user.mjs

// like vscode extension `import vscode from 'vscode``
import { gm } from 'https://modern-esm-cdn/@xxx-monkey/runtime'

// `importShim` if impl is using shim mode
import { importShim } from 'https://modern-esm-cdn/@xxx-monkey/runtime'

import bar from 'https://modern-esm-cdn/bar'
import baz from 'https://modern-esm-cdn/baz'

// or like https://developers.cloudflare.com/dynamic-workers/api-reference/
// export default { fetch }
export default { userscript }

// or like vscode extesion style
// export { activate, deactivate }
export { userscript }

Maybe impl using

• or import shim https://github.com/guybedford/es-module-shims

• or faster rust bundler https://github.com/rolldown/rolldown, like vite, see https://v7.vite.dev/guide/rolldown

modules

There are many JS modules.

• ESM: import/export
• CJS: require
• legacy: window/globalThis/self/...
• UMD
• AMD
• SystemJS

library

• Since 2021, famous dev sindresorhus move all his 1K+ packages to ESM only, see The ESM move sindresorhus/meta#15

• In 2026, popular library I known are ALL written ESM format.

• In 2026, ZERO popular library I known is written CJS format, or legacy global IIFE format, ...

CDN

Many CDN support ESM

• Since 2020, import XXX from 'https://esm.sh/{{pkg}}', see https://github.com/esm-dev/esm.sh

• Since 2020, import XXX from 'https://cdn.jsdelivr.net/npm/{{pkg}}/+esm', see Introducing esm.run - A New-Age CDN for JavaScript modules jsdelivr/jsdelivr#18263

• Since 2020, import XXX from 'https://cdn.skypack.dev/{{pkg}}', see https://github.com/skypackjs/skypack-cdn

frontend

<script type="module" src="module.js"></script>

import pkg from 'https://url/pkg'

• Since maybe 2018, firefox maybe v60, support ESM

• Since maybe 2017, chrome maybe v61, support ESM

backend

import pkg from 'pkg'

• Since 2017, nodejs v8.5.0, support ESM, see module: Allow runMain to be ESM nodejs/node#14369 nodejs/node@c8a389e

import pkg from 'https://url/pkg'

• Since maybe 2018, deno born, support ESM

• Since maybe 2021, bun born, support ESM

embed

• Since maybe 2020, quickjs born, support ESM

editor

• Since 2021, vscode extension is migrating to ESM, see Enable consuming of ES modules in extensions microsoft/vscode#130367

userscript

• AFAIK, non userscript loader assuming ESM and support ESM yet.

workaround/polyfill/shim

• Since 2018, guybedford/es-module-shims bring ESM to non-ESM environment, see https://github.com/guybedford/es-module-shims

related

FR matrix in lines ascending order

greasemonkey/greasemonkey#3229

#2791

violentmonkey/violentmonkey#2528

upstream

• votes for firefox

https://connect.mozilla.org/t5/ideas/enable-consuming-of-es-modules-in-content-scripts-and/idi-p/125953