Split branch into one branch per folder

gh-branch-split

#!/bin/bash
set -e

branchToSplit="feat/react/deprecated-react-node-array"
title="Remove usage of deprecated ReactChild"
message="This PR removes the usage of the deprecated \`ReactChild\` type (see https://github.com/DefinitelyTyped/DefinitelyTyped/discussions/64451)."

mergeBase=$(git merge-base origin/master $branchToSplit)
types=( $(git diff --name-only $mergeBase $branchToSplit | grep -oE 'types/[^/]+/' | cut -d/ -f2 | uniq) )

for type in "${types[@]}"; do
    echo "Splitting $type"

    branchName="$branchToSplit-split/$type"
    git checkout -b "$branchName" master
    git checkout "$branchToSplit" -- "types/$type"
    prTitle="[$type] $title"
    git commit -a -m "$prTitle"
    git push -u origin HEAD
    gh pr create \
        --title "$prTitle" \
        --body "$message";
done