remove-unused-vars

Remove more unused variables. Highly experimental.

[!WARNING]

There's a reason linters don't fix the unused variables, even with a flag like --unsafe or --fix-dangerously.

Modern linters can fix a lot of issues automatically, but don't always remove all unused variables and types. Even when using --unsafe or --fix-dangerously.

Use remove-unused-vars to remove everything the linter finds. Then run QA and review if there's anything that might need reverting. Needless to say, Git's your friend here!

Don't use e.g. eslint --fix or biome lint --write when piping to remove-unused-vars, otherwise the positions to remove things might not match up. Use the linter first to have it remove whatever it can, then proceed with the command(s) below.

[!TIP]

Use this with Knip for a cruel code crusher experience.

Install

npm install -D remove-unused-vars

Pipe JSON

Pipe the JSON-formatted output of the linter to remove-unused-vars

Add to package.json#scripts, modify the commands below and make sure to use local linter configuration.

ESLint

eslint --rule 'no-unused-vars: error' --quiet -f json | remove-unused-vars

typescript-eslint

eslint --rule 'no-unused-vars: off' --rule '@typescript-eslint/no-unused-vars: error' --quiet -f json | remove-unused-vars

Biome

biome lint \
  --only correctness/noUnusedVariables \
  --only correctness/noUnusedImports \
  --only correctness/noUnusedFunctionParameters \
  --reporter json | remove-unused-vars

oxlint

oxlint -A all -D 'no-unused-vars' -D '@typescript-eslint/no-unused-vars' -f json | remove-unused-vars

From JSON file

Alternatively, provide a JSON file as the first argument to remove-unused-vars, for example:

oxlint -A all -D '@typescript-eslint/no-unused-vars' -f json > unused-vars.json
remove-unused-vars unused-vars.json

Without installation

Use something like this without installing remove-unused-vars:

eslint -- --quiet --format json | npx -y remove-unused-vars