VSCode Extension Development

Extension locations

Extensions live in vscode_extensions/<name>/. Each has:

• src/extension.ts — main source code
• dist/extension.js — compiled output (esbuild)
• install/<name>-<version>.vsix — packaged extension
• package.json — manifest with activation events, commands, config

Build & install workflow

CRITICAL: VSCode runs the installed .vsix from ~/.vscode/extensions/, NOT the dist/ in the repo. After every code change you MUST:

1. Compile: cd vscode_extensions/<name> && npm run compile
2. Package: npx @vscode/vsce package --out install/<name>-<version>.vsix
3. Install: code --install-extension install/<name>-<version>.vsix --force
4. Tell user to reload: Cmd+Shift+P → “Developer: Reload Window”

Just running npm run compile is NOT enough — the user will still see old behavior.

Verifying installed code

To check what code is actually running:

# Check installed extension has your changes
grep "some_unique_string" ~/.vscode/extensions/<publisher>.<name>-<version>/dist/extension.js

Common pitfalls

• esbuild watch mode: npm run compile may start a watcher that blocks. This is fine for compilation but you still need to package + install.
• Version conflicts: If the installed .vsix version matches, VSCode may cache. Use --force flag on install.
• Extension host: Changes only take effect after “Developer: Reload Window”.