cmd - Why does filtering output of git diff with findstr using a regular expression to get just lines ending with .js not work? -

i'm working on first javascript project. advised me use eslint git pre-hook check code. i'm writing own pre-hook pass eslint (only changed files checked). i'm trying find every file .js extension. tried following solutions none working:

git diff --cached --name-only --diff-filter=acm | findstr /r  ".js$"  => returns nothing git diff --cached --name-only --diff-filter=acm | findstr /r  ".js"   => returns .js , .json git diff --cached --name-only --diff-filter=acm | findstr /r  ".js^$" => returns nothing 

could me regular expression find every file .js extension?

open command prompt window , run findstr /? output of standard windows console application.

there perhaps no need regular expression find @ all. simple case-insensitive (/i) interpreted literal (/l) search string additional option match lines ending (/e) string enough.

git diff --cached --name-only --diff-filter=acm | findstr /e /i /l .js 

another solution using /c: results in interpreting search string default literal string (in cases) except option /r used forcing regular expression interpretation.

git diff --cached --name-only --diff-filter=acm | findstr /e /i /c:.js 

but in case of lines output git have trailing spaces or horizontal tabs necessary use case-insensitive regular expression find.

git diff --cached --name-only --diff-filter=acm | findstr /i /r /c:"\.js[    ]*$" 

. must escaped backslash in search expression interpreted literal character instead of regular expression meaning of character.

please note 1 character in square bracket space character , other 1 horizontal tab character. tab character displayed above , below according html standard sequence of 1 or more spaces.

in case better use batch file difficult "type" tab character in command prompt window.

git.exe diff --cached --name-only --diff-filter=acm | %systemroot%\system32\findstr.exe /i /r /c:"\.js[  ]*$" 

it advisable in batch file specify files/scripts execute file extension , if possible full path make batch file independent on current values of environment variables path , pathext as possible.