How to lint only changed files?

lint-only-changed-files.MD

Updated on medium

find out the differences

use git diff to generate file list

git diff --name-only master

limited to certain file types

add ext filter

git diff --name-only master | grep -E "(.js$|.ts$|.tsx$)"

handle the case of file removal

ignore deleted files

git diff --name-only --diff-filter=ACMRTUXB master | grep -E "(.js$|.ts$|.tsx$)"

node scripts

add eslint to package.json

....
"scripts":
  "lint:script": "eslint -c eslintrc.js $(git diff --name-only --diff-filter=ACMRTUXB master | grep  -E \"(.js$|.ts$|.tsx$)\")"

CI script

sample with circle ci here

....
"scripts":
 "lint:script": "eslint -c eslintrc.js $(git diff --name-only --diff-filter=ACMRTUXB origin/master | grep  -E \"(.js$|.ts$|.tsx$)\")"

for stylelint

will need grep fallback for empty result cases

 
 ....
 "scripts":
   "lint:style": "stylelint --config .stylelintrc.js $(git diff --name-only --diff-filter=ACMRTUXB origin/master | grep  -E \"(.js$|.ts$|.tsx$)\" || echo \".stylelintrc.js\")"

NOTE: make sure our local branch is up to date (merge origin/master)

Why not use the --cached option for eslint?

https://eslint.org/docs/latest/user-guide/command-line-interface#caching

I check this solution and it is not better then use cache.

Just slightly adapted it for sqlfluff, another linter - and it works like a charm! thanks!