Lesson 3 • Intermediate
Branching and Merging 🌿
Create isolated branches to build features, merge them back safely, and learn when to rebase vs merge — the skill that unlocks team collaboration.
What You'll Learn in This Lesson
- • Creating, switching, and deleting branches
- • Fast-forward vs three-way merges
- • Rebase for clean, linear history
- •
git stash— save work temporarily - • The golden rule of rebasing
git init test-branching to practice safely.1️⃣ Branch Basics
A branch is just a pointer to a commit. Creating a branch is nearly instant — Git doesn't copy files, it just creates a new pointer. This makes branching incredibly lightweight.
Try It: Branch Basics
Create, list, and switch between branches
// Branches — Work in Isolation
console.log("=== What Are Branches? ===");
console.log("A branch is an independent line of development.");
console.log("The default branch is called 'main' (or 'master').");
console.log();
console.log("=== Why Branch? ===");
console.log("• Work on a feature without breaking main");
console.log("• Multiple people work on different things simultaneously");
console.log("• Experiment safely — delete the branch if it fails");
console.log("• Keep main always deployable
...2️⃣ Merging Branches
Merging brings changes from one branch into another. Fast-forward merges simply move the pointer. Three-way merges create a merge commit when both branches have diverged.
Try It: Merging
Fast-forward and three-way merges visualized
// Merging — Combining Branches
console.log("=== git merge — Bring Changes Together ===");
console.log();
console.log("Steps to merge a feature branch into main:");
console.log(" 1. $ git checkout main ← Switch to target");
console.log(" 2. $ git merge feature-login ← Merge feature into main");
console.log();
console.log("=== Fast-Forward Merge ===");
console.log("When main hasn't changed since the branch was created:");
console.log();
console.log(" Before: main: A ── B");
conso
...3️⃣ Rebase vs Merge
Rebase replays commits on top of another branch for a clean, linear history. It's powerful but dangerous if used on shared branches. Follow the golden rule: never rebase pushed commits.
Try It: Rebase
Understand when to rebase and when to merge
// Rebase vs Merge
console.log("=== git rebase — Linear History ===");
console.log();
console.log("Rebase replays your commits on top of another branch,");
console.log("creating a clean, linear history.");
console.log();
console.log("=== Before Rebase ===");
console.log(" main: A ── B ── E ── F");
console.log(" \\");
console.log(" feat: C ── D");
console.log();
console.log("=== After: git rebase main (on feat branch) ===");
console.log(" main: A ── B ── E ── F");
conso
...4️⃣ git stash — Quick Save
git stash temporarily shelves your changes so you can switch branches. When you come back, git stash pop restores everything exactly as it was.
Try It: git stash
Save work temporarily and restore it later
// git stash — Save Work Temporarily
console.log("=== git stash — Quick Save ===");
console.log("Stash saves your uncommitted changes and cleans your working directory.");
console.log("Perfect when you need to switch branches mid-work.");
console.log();
console.log("=== Scenario ===");
console.log("You're working on feature-login but need to fix a bug on main:");
console.log();
console.log(" 1. $ git stash ← Save current changes");
console.log(" Saved working directory and ind
...⚠️ Common Mistakes
git branch -d name after merging.git log --oneline --graph --all to visualize your entire branch structure in the terminal.📋 Quick Reference
| Command | Purpose |
|---|---|
| git branch name | Create a branch |
| git switch -c name | Create and switch |
| git merge branch | Merge branch into current |
| git rebase main | Replay on top of main |
| git stash / pop | Save/restore work |
| git branch -d name | Delete merged branch |
🎉 Lesson Complete!
You now understand branching, merging, and rebasing! Next, we'll push your code to GitHub and learn remote repository workflows.
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