fastlint

library1.1.0jsnpmunverified

fastlint is a command-line tool (v1.1.0) that speeds up linting by running linters only on files changed in git — either in the working copy, staged, or compared to branches like master. It avoids running on unchanged files, integrating with eslint and other tools via piped filenames. Key features: --staged filter, --diff-filter (A/C/D/M/R/etc.), --glob filtering, and multiple path output modes. Stable, low maintenance, single-purpose tool. Alternatives include lint-staged and husky, but fastlint is more flexible for branch comparison.

devops testing

npm install fastlint

package ↗

INSTALL

IMPORT

SIG · FASTLINT

fastlint

devopsjavascriptv1.1.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

fastlint

✓ npx fastlint ...

✗ require('fastlint')

fastlint is a CLI tool, not a library. Use via npx or global install.

fastlint binary

✓ fastlint --version

✗ fastlint.start()

Always invoked from shell, not programmatically.

Installs fastlint, creates a git repo, makes a change, then lints only changed files with eslint.

npm install -g fastlint && echo "console.log('hello')" > test.js && git init && git add test.js && git commit -m "init" && echo "console.log('world')" >> test.js && fastlint HEAD~1 HEAD --print0 | xargs -0 npx eslint

fastlint --version

Debug

Known issues

gotcha--diff-filter=Q includes untracked files, not 'Deleted' as some might assume.

fix

Use correct letter: Q for untracked, D for deleted.

affects: all

gotchaDefault behavior includes working copy changes if no branch arguments given; may surprise users expecting empty output.

fix

Always specify two branches or use --working-copy explicitly.

affects: all

Errors

Common errors & fixes

fastlint: 'origin/master' is not a valid git reference

Typo or remote not fetched; branch name incorrect.

fix

Use 'origin/main' or 'master' if local branch exists.

fatal: ambiguous argument 'HEAD~5 HEAD': unknown revision or path

Missing space between revisions and paths, or incorrect syntax.

fix

Use correct form: fastlint <since> <until>, e.g. 'HEAD~5 HEAD'.

fastlint: option '--print0' requires a value

Using --print0 as a boolean flag; it's fine, but if followed by argument, fails.

fix

Place --print0 at end of options before xargs.

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

packagehttps://www.npmjs.com/package/fastlint ↗