Run prettier for PR files

fancy_prettier_PR.sh

#!/usr/bin/env bash
# chmod +x this and save in your PATH. Assumes `prettier` is in your `devDependencies` already
BASE=$(git merge-base master HEAD) # change master to whatever your trunk branch is
FILES=$(git diff --name-only $BASE HEAD | xargs)

npx prettier --list-different $FILES

# Want eslint too?
# npx eslint --ignore-path=.prettierignore $FILES

prettier_PR.sh

# npx or yarn
# change "git diff develop" to "git diff <trunk_branch_name>", or whatever branch you're targeting in the PR
yarn prettier -w $(git diff develop --name-only | grep '.js' | xargs)

Found at: https://stackoverflow.com/questions/47610213/how-do-i-run-prettier-only-on-files-that-i-want-to-commit