2.5.4Lesson 2.5.4: Branches

The idea

Until now, each commit came after the previous one, in a single line: the main branch.

A branch is another line of commits that starts from there. You try whatever you like on it, and main stays untouched. If it works out, you join the two; if not, you throw it away.

Creating a branch and switching to it

$ git switch -c goodbye

Switched to a new branch 'goodbye'

-c creates it. git branch lists the branches, with * next to the current one:

$ git branch

* goodbye
  main

Working on it

Add this at the end of hello.js:

console.log("Goodbye");

And save it in a commit, as always:

$ git add hello.js
$ git commit -m "feat(greeting): add the goodbye"

Back to main

$ git switch main

Look at hello.js: the goodbye isn't there. That line only exists on the other branch.

Joining the branches

From main, bring in what's on the other branch:

$ git merge goodbye

Updating 7b1e0d4..9c2f5a8
Fast-forward
 hello.js | 1 +
 1 file changed, 1 insertion(+)

Now main has the goodbye. The branch isn't needed any more:

$ git branch -d goodbye

If both change the same thing

If both branches changed the same line, Git doesn't know which to keep: that's a conflict. It marks the file with both versions, you keep the right one, and you add and commit. VS Code shows it with buttons to choose.

Try it

$ git switch -c table-of-5
$ git add table.js
$ git commit -m "feat(table): switch to the 5 times table"
$ git switch main
$ git merge table-of-5
$ git branch -d table-of-5

Summary

• A branch is a separate line of work; the main one is main.
• git switch -c name creates a branch and switches to it; git switch main goes back.
• git merge name brings the other branch's work into the current one.
• If both changed the same line, there's a conflict and you choose.