Tracker
Personal tracker for DSA interview prep, plus a few small side apps. It's a plain static site with no build step, deployed on Vercel at https://tracker-roan-nine.vercel.app/. Every push to the connected branch redeploys it.
What's in here
| Path | What it is |
|---|
index.html | DSA Notebook, the main app. Dashboard, 16 topics, 600+ questions, practice sessions (Worked / Graded / Mock), spaced-repetition revision, daily question, streaks, notes, pins, search. |
js/data.js | Topic and question data, plus the localStorage helpers for progress, notes and revision state. |
js/sync.js | Cross-device sync through a private GitHub gist. Shared by every app. |
js/back-button.js | Floating "← Tracker" pill on every standalone page (dsa/, apps/, google/, visuals/, sysdesign/). |
dsa/*.html | One cheatsheet per topic, plus the master map, thoughts and JS built-ins pages. |
google/*.html | Google prep hub, interview sources and onsite log. They're shown inside the main app's Google view. |
visuals/visuals.html | Image cheat sheets (inline SVG cards, one picture per idea). Shown inside the main app's Visuals view. |
sysdesign/system-design.html | System design notes, one card per topic. Linked from the sidebar bottom. |
apps/gym-5day.html | 5-day PPL workout tracker. |
apps/habits.html | Habits tracker (its own PWA: habits-manifest.json, habits-sw.js). |
docs/ | Prompts and personal notes (docs/notes). |
sw.js, manifest.json | Service worker and manifest for the main PWA (works offline). |
test/ | Node tests. |
vercel.json | Security headers, including the Content-Security-Policy. |
All state lives in the browser's localStorage. Nothing is stored on a server.
Run it locally
No install step. Serve the repo root with any static server and open index.html:
python3 -m http.server 8000
# then open http://localhost:8000
Opening the file directly (file://) won't work properly because of the service worker and the page loading other files.
Tests
node --test test/*.test.js
The tests load js/data.js and the inline script from index.html into a Node vm with a fake localStorage, so they check state logic (grading, sync, security rules, link integrity), not how things look in a real browser.
Cloud sync
Paste a GitHub token once per device (a fine-grained token with only the Gists permission, or a classic token with the gist scope). Data is synced to one private gist called tracker-sync-v1, one JSON file per app. The token is stored only in that browser's localStorage.
- The DSA notebook and the gym app upload a few seconds after every edit. The habits app syncs after its own edits.
- If two devices both changed things, the data is merged entry by entry rather than one device overwriting the other. If both changed the same entry, the most recently edited side wins.
- Safety nets: the previous cloud copy is kept as
<app>.prev.json in the gist (GitHub also keeps gist revision history), and each device keeps its last three pre-sync snapshots in localStorage (<app>-presync, -presync-2, -presync-3).
- Known limit: there are no per-entry timestamps, so deleting something on one device can be undone by another device that still has it.
Deploying
Pushing to the branch Vercel watches deploys automatically. Pull requests get a Vercel preview URL if the Vercel GitHub integration is on for this repo. The service worker serves HTML and JS network-first, so a new deploy shows up on the next load.
