git-worktree

Create worktrees that reuse the main repo's installed packages via symlinks. Reinstalling is never needed unless the branch changes package.json.

Steps

Run from inside the main repo directory. The main repo's directory name is resolved dynamically — no hardcoded repo name:

BRANCH=$1
MAIN="$(basename "$(git rev-parse --show-toplevel)")"   # the main repo's dir name
git fetch origin
# Resolve the remote's default branch (main, master, …) — don't hardcode "main".
BASE="$(git symbolic-ref --quiet --short refs/remotes/origin/HEAD 2>/dev/null)"
[ -n "$BASE" ] || { git rev-parse --verify --quiet origin/main >/dev/null \
  && BASE=origin/main || BASE=origin/master; }
# Create the worktree directly ON the branch — never check out afterwards (that
# would detach HEAD and abandon $BRANCH).
if git show-ref --verify --quiet "refs/heads/$BRANCH"; then
  git worktree add "../$BRANCH" "$BRANCH"                 # existing local branch
else
  git worktree add -b "$BRANCH" "../$BRANCH" "$BASE"      # new branch off the default
fi
cd "../$BRANCH"
ln -snf "../$MAIN/node_modules" .
ln -snf "../$MAIN/.env" .
[ -f "../$MAIN/.env.prod" ] && ln -snf "../$MAIN/.env.prod" .   # only if it exists

The worktree is now checked out on $BRANCH (a new branch off the remote's default branch, or the existing one). The symlinks are relative to the worktree dir, so ../$MAIN/ resolves to the sibling main-repo checkout the worktree was created next to.

Rules

• Never run npm install / yarn / pnpm install inside the worktree unless package.json differs from main.
• Only symlink files that exist in main — the [ -f ... ] guard skips a missing .env.prod.
• Remove when done: git worktree remove "../<branch>".

Verify

MAIN="$(basename "$(git rev-parse --show-toplevel)")"
ls -la node_modules .env
# node_modules -> ../<MAIN>/node_modules
# .env -> ../<MAIN>/.env