6. Checkpoint A — Fundamentals + DOM
JavaScript · 56 pages source format
Before async and modules, prove you can write clean functions, transform data with array methods, and ship a working DOM app. Pass criteria are non-negotiable — fix gaps before Phase C.
What you'll learn
- Self-assessment checklist
- Portfolio habit: commit early
Pass criteria
You pass when all six are true. Audit your work. Fix failures before continuing.
- 5+ pure utility functions (no DOM, no I/O) with clear names
- Used map/filter/reduce on real data — not index loops
- Todo app: add, toggle, delete, filter, localStorage persist
- No var, no == in new code
- Code pushed to GitHub with meaningful commits
- Can explain block scope vs function scope aloud in 60 seconds
Do this now
Go through each criterion. Mark pass/fail in your README. Fix failures this week.
Code review yourself
Re-read your todo app. Rename vague variables. Extract repeated DOM logic into functions. Remove dead code.
Do this now
Spend 30 minutes refactoring. Commit with message "refactor: checkpoint A cleanup".
Explain it
If you cannot explain event delegation or why const is default, you are not ready for async. Teach a rubber duck.
Do this now
Record a 2-minute voice memo walking through your todo app architecture.