Stage 3 - Tracking Changes Effectively

At the end of Stage 2, task-service has three commits. Now imagine you edit task-service.js to prevent duplicate tasks and at the same time fix wording in README. Before creating the next commit, you must inspect what exactly changed.

Git file lifecycle

Why seeing changes is the core discipline

Without inspected diffs, commit history becomes a blur. You lose the difference between “I touched this block by accident” and “this change supports the story we planned.”

In task-service, make three changes:

update task validation in task-service.js;
append a usage example to README.md;
create notes.txt with a temporary thought.

Now run:

git status

It will show both README.md and task-service.js as modified. notes.txt might be untracked.

Compare before commit, not after

git diff answers: what has changed in the working directory but is not staged yet?

git diff

git diff --staged answers: what will the next commit contain?

git add task-service.js
git diff --staged

This split is crucial when a learner wants to avoid mixing unrelated concerns, for example “fix duplicates” and “rewrite docs tone”. Keep those separate if the intent differs.

Correcting with intent, not panic

If you made a wrong local edit in notes.txt, you can discard it:

git restore notes.txt

If you staged task-service.js too early and need more edits before commit:

git restore --staged task-service.js

Now the edit returns to working state and remains recoverable. You did not lose work, just moved it back one step.

Renaming and removing in real projects

Sometimes requirements change and a file no longer belongs to the project. Use:

git rm notes.txt
git commit -m "docs: remove obsolete scratch note"

If you just want to move a file from root into a docs folder, first create the docs folder in Finder, File Explorer, or your IDE. Then run:

git mv README.md docs/README.md
git add docs/README.md
git commit -m "docs: move main README to docs"

git mv is clear about intent and usually easier to review than moving by file manager first.

Situation	Helpful command	Decision it enables
Review local edits	`git diff`	Commit only what is correct and complete
Review staged edits	`git diff --staged`	Verify the exact commit payload
Cancel accidental local edit	`git restore`	Remove noise before commit
Move or remove file	`git mv` / `git rm`	Keep history coherent

Practice tied to this stage

Modify only task-service.js to reject duplicates.
Add two lines to docs/README.md and one to notes.txt.
Stage only task-service.js and docs/README.md and commit.
Check git status, then discard or restage notes.txt as intended.

You now have the right posture for all later team stages: inspect before commit, and make each commit tell one clear story.