eslint-plugin-diff

eslint-plugin-diff

Run ESLint on your changed lines only. Now with CI support!

What problem does it solve?

Introducing new ESLint rules (or updating 3rd party configs) in a large codebase can be tedious. This plugin allows your team to ease into new rules by only linting all new/modified code, eventually migrating to the new/updated rules.

It can be used in CI environments as well.

Installation

$ yarn add -D eslint-plugin-diff

Usage

If you want to define which commit or commit-range to diff between (useful in CI), you can set the environment variable ESLINT_PLUGIN_DIFF_COMMIT (otherwise the plugin will default to HEAD):

$ ESLINT_PLUGIN_DIFF_COMMIT="a8fdc20..5a9f19c" yarn run eslint .
# or
$ ESLINT_PLUGIN_DIFF_COMMIT="${GITHUB_SHA}.." yarn run eslint .

See git's official documentation on the syntax

It's recommended to use "plugin:diff/diff" (see config).

Config diff — Diff all changes since HEAD (staged and unstaged)

Extend your config in .eslintrc:

{
  "extends": ["plugin:diff/diff"]
}

Equivalent to git diff HEAD

Config staged — Diff staged changes only

Useful for pre-commit hooks, e.g. when running ESLint with lint-staged

Extend your config in .eslintrc:

{
  "extends": ["plugin:diff/staged"]
}

Equivalent to git diff HEAD --staged