Removing Unused Dependencies and Exports

Trimming away unused dependencies and exports

Knip is a tool that helps us trim away unused dependencies and exports from our packages. It works well with monorepos, and it’s a great way to detect extraneous dependencies, and potentially dead code (or over-exposed code) that TypeScript and ESLint aren’t sophisticated enough to detect.

Install it

sh
pnpm i -D knip

We need a small config file to tell Knip about entry points

json
{
 "workspaces": {
  "packages/*": {
   "entry": ["src/{index,main}.ts"],
   "project": ["src/**/*.{ts,tsx,svelte}"]
  }
 },
 "ignoreDependencies": [
  "syncpack",
  "@testing-library/svelte",
  "@tsconfig/svelte",
  "@vitest/coverage-v8"
 ]
}

Run it

sh
pnpm knip

You’ll see a report of unused dependencies and exports. You can also run it with the --fix flag to remove the unused dependencies and exports.

You may notice that sometimes it removes the export of a symbol, but doesn’t actually remove the code itself. Think about sequencing and how you could both remove the export and detect the dead code (have we been using another tool that might help detect an unused function or variable?)