Convert to ESM

[ntotten]

• Convert code to ESM
• Desktop extension runs as pure esm
• Web extension is bundled as cjs
• Also cleans up tests to make them run faster and improve reliability
• Everything is async, no more blocking the loop

[Copilot]

Pull request overview

This PR converts the Prettier VS Code extension from CommonJS to ECMAScript Modules (ESM), enabling modern JavaScript module support and improving compatibility with Prettier v3+. The conversion involves significant architectural changes while maintaining backward compatibility with Prettier v2.

Key Changes

• Module System: Converted to pure ESM with "type": "module" in package.json, requiring .js extensions on all imports
• Dynamic Loading: Replaced worker thread-based Prettier loading with native ESM import() for both Prettier and plugins
• Build Configuration: Desktop extension outputs as ESM (.js), browser extension as CJS (.cjs), and tests as bundled CJS (.cjs)

Reviewed changes

Copilot reviewed 47 out of 49 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
package.json	Added "type": "module", updated entry points, removed find-up and resolve dependencies
package-lock.json	Contains outdated dependencies that need regeneration
tsconfig.json / tsconfig.test.json	Updated to ESM with module: "ESNext" and moduleResolution: "bundler"
esbuild.mjs	Configured ESM output for desktop, CJS for browser/tests, added Node.js built-in externals
src/ModuleResolver.ts	Complete refactor: removed find-up/resolve deps, added async module resolution with findUp utility
src/PrettierDynamicInstance.ts	New unified loader using dynamic import() for both ESM and CJS Prettier modules
src/PrettierEditService.ts	New loadPlugins() function to load plugins via dynamic import with pathToFileURL
src/utils/find-up.ts	New async utility replacing find-up package
src/utils/exec.ts	New async utility for executing shell commands with proper timeout handling
src/utils/resolve-module-entry.ts	New utility to resolve package.json entry points for ESM compatibility
src/utils/global-node-paths.ts	Converted to async, added pnpm support, uses new execAsync utility
src/utils/resolvers.ts	Removed loadNodeModule(), updated resolveNodeModule() to use createRequire()
src/test/**/*.test.ts	Updated imports to use .js extensions and assert module (not node:assert)
test-fixtures/config/**/*.js	Converted Prettier config files from module.exports to export default
.vscode/launch.json	Updated test configuration to use new test setup
.vscode-test.mjs	Updated to look for .cjs test files

Comments suppressed due to low confidence (1)

src/utils/resolvers.ts:44

• The resolveConfigPlugins function is exported but is no longer used anywhere in the codebase. Plugin resolution is now handled directly in PrettierEditService.loadPlugins() via dynamic imports. Consider removing this function, or if it's intended for future use or external API, add a comment explaining why it's kept.

[fisker]

Why don't we try both import and require? require still avaiable in ESM.

Just to be clear, directory import is for v2, right? Since Prettier 3 already dropped support for it.

[fisker]

I don't know much about vscode extensions, but the code looks good to me.