lint-staged Module

The problem

Running the whole linter on every commit is the reason teams disable their pre-commit hook. lint-staged fixes that by running the tools only on the files that are actually staged, which usually turns a ten-second lint into a half-second one.

The part that is easy to copy wrong is where the configuration lives. In a single repository the lint-staged key in package.json is enough. In a monorepo the packages are installed per workspace, and a root-level configuration has to be a separate file for the resolution to work.

The command

npx create-devflow --only lint-staged

lint-staged depends on Husky, so the Husky module is resolved and applied automatically.

Generated files

Single repository — merged into package.json

{
  "lint-staged": {
    "*.{js,jsx,ts,tsx}": ["eslint --fix", "prettier --write"],
    "*.{json,md,yml,yaml,css,scss}": ["prettier --write"]
  }
}

Monorepo — lint-staged.config.mjs

export default {
  "*.{js,jsx,ts,tsx}": ["eslint --fix", "prettier --write"],
  "*.{json,md,yml,yaml,css,scss}": ["prettier --write"]
};

When the Biome module is used instead of ESLint and Prettier, the mapping becomes:

export default {
  "*.{js,jsx,ts,tsx,json,css}": ["biome check --apply"]
};

Packages installed

Scripts added

None. lint-staged is invoked from the Git hook, not from an npm script.

Manual setup versus DevFlow

The manual version is npm i -D lint-staged and then writing the glob map. The glob map is where the copy-paste goes wrong most often: matching *.{js,jsx,ts,tsx} but forgetting that .json, .md and .yml also need formatting, or forgetting to exclude lock files.

DevFlow writes both glob groups and picks the correct file location based on whether the project is a monorepo.

Limits

• The configuration assumes ESLint and Prettier are installed. The lint-staged module does not install them. Apply the ESLint module and the Prettier module as well, or the hook will fail with a "command not found".
• The Biome variant only applies when the formatter option is set to Biome. It is not detected automatically from an existing biome.json.
• Single-repository mode writes into package.json. The lint-staged key is merged, and existing keys are not replaced — a key you already had stays as it was.

FAQ

Do I need lint-staged?

No, but it is recommended. Without it the Husky pre-commit hook runs the full npm run lint, which becomes slow on larger codebases.

Where does the configuration live?

In package.json for a single repository, and in lint-staged.config.mjs for a monorepo. DevFlow picks the right one based on the detected repository type.

Does it work with pnpm and yarn?

Yes. The hook calls npx lint-staged, which resolves the binary from the local node_modules/.bin regardless of the package manager.

Related

• Husky module — the hook that triggers lint-staged
• ESLint module and Prettier module — the tools it runs
• ESLint, Prettier and Husky setup for React and TypeScript