A focused macOS scratchpad for practising the JavaScript and TypeScript questions that keep coming up in front-end interviews.
Twenty-four classic interview problems, each with a written brief, worked examples and a hidden test suite. Pick a question, write the solution in a real editor, run the tests, and ask Claude when you get stuck.
No browser tabs, no sign-in, no scoreboard. Your work is saved on your Mac and stays there.
Monaco, the editor from VS Code, with full language services: completion, hover types, inline diagnostics and go-to-definition. Switch a question between JavaScript and TypeScript at any time and the starter code, examples and tests all switch with it. TypeScript starters come with the interfaces already written, so you implement against a real signature.
Every question ships with a hidden suite. Hit Run tests and the results appear in the
panel below the editor, alongside a console for your own console.log calls. Your code runs
in a separate sandboxed process, so an infinite loop costs you a click rather than the app.
Easy, Medium and Hard are not three different questions. They are the same question with more asked of you, and each level includes everything below it.
debounce at Easy just has to delay the call. At Medium it also needs cancel. At Hard it
needs flush as well. The brief, the examples and the hidden tests all move together, so
what you are shown always matches what you are marked on.
Stuck on a question, or want your working solution critiqued? The AI panel reviews the code you have actually written against the brief you are actually on. It runs on your own Anthropic API key, and code is only ever sent when you press send.
A grid of every question against every level, so you can see the gaps rather than guess at them. Each cell records one of three states: practised, completed with help, or solved on your own. The distinction matters, because a question you only finished with the AI panel open is not one you have learned yet.
Built into the toolbar, because the point is to practise for twenty-five minutes, not to open the app and reorganise your folders.
- Autosave. Your work in progress survives a quit, per question and per language.
- Auto-run. Tests can re-run as you type, so the feedback loop stays tight.
- Your key, your keychain. The Anthropic key is stored in the macOS keychain, never in a config file.
- Automatic updates. New releases install themselves.
| Foundations | Data and objects | Advanced |
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Each one is available in both JavaScript and TypeScript, at all three levels.
Grab the latest signed and notarised build from the
Releases page. Open the .dmg, drag Practice Pad into
Applications, and launch it like any other Mac app.
Built for Apple Silicon (arm64) Macs, macOS 11 Big Sur or newer.
The AI panel needs a key. Everything else in the app works without one.
- Create a key on the Claude Platform.
- Open Practice Pad and click the gear icon.
- Paste the key in and save.
It is stored encrypted in the macOS keychain on your device. Anthropic API usage is billed separately from a Claude subscription.
Proprietary. Copyright © 2026 Michael Sydney Moore, all rights reserved. See LICENSE.
Builds here are licensed for personal use, not sold, and may not be redistributed or reverse engineered. Bundled third-party components (Electron, Monaco Editor, React and others) keep their own licences, and their notices ship with the application.