feat: add snake game example

[shaktipy]

Overview

This PR adds a classic Snake Game as a new example in the examples/snake-game directory. It demonstrates how to build an interactive terminal game using TermUI's widget system.

Features

• 🎮 Movement – Arrow keys or WASD
• 🍎 Food collection – Eat food to grow and increase score
• 💥 Collision detection – Walls and self-collision end the game
• 🔁 Restart – Press R after game over
• 🚪 Exit – Press Q to quit

Technical Implementation

• Custom SnakeBoard widget renders the game grid
• SnakeGame widget manages game state and logic
• Uses TermUI lifecycle methods: onMount, onUnmount, handleKey, _renderSelf
• Game loop with setInterval at 150ms tick rate
• Fully typed TypeScript

How to Run

cd examples/snake-game
bun install
bun run dev

## Fixes #522 

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

* **New Features**
  * Added a playable Snake game example with keyboard controls (WASD/arrow keys), real-time score, food consumption, and restart on game-over.
  * Includes collision detection for walls and self-intersections and a centered fullscreen demo with graceful exit keys.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: b1b04728-9463-4977-97bb-ea2d8d4d20b7

📥 Commits

Reviewing files that changed from the base of the PR and between 5f0657f and fbc91c4.

⛔ Files ignored due to path filters (1)

• bun.lock is excluded by !**/*.lock

📒 Files selected for processing (1)

• examples/snake-game/src/index.tsx

🚧 Files skipped from review as they are similar to previous changes (1)

• examples/snake-game/src/index.tsx

---

📝 Walkthrough

Walkthrough

Adds a new playable Snake example under examples/snake-game/ with package/tsconfig, a SnakeBoard renderer, SnakeGame state and tick loop (movement, collisions, food, scoring), keyboard input handling, and a main() bootstrap to mount the App.

Changes

Snake Game Example

Layer / File(s)	Summary
Project configuration and dependencies examples/snake-game/package.json, examples/snake-game/tsconfig.json	Package metadata defines the example as a private ESM module with dev, build, and typecheck scripts; TypeScript config targets ES2022 with JSX via @termuijs/jsx, strict settings, and workspace deps on core and widgets.
Game board constants and rendering examples/snake-game/src/index.tsx (constants, SnakeBoard)	Grid dimensions and tick interval constants; SnakeBoard widget renders snake and food onto a character grid and reacts to state updates.
Game state initialization examples/snake-game/src/index.tsx (SnakeGame constructor)	SnakeGame initializes title, score, board, snake position/direction/score and generates initial food avoiding the snake body.
Game mechanics and lifecycle examples/snake-game/src/index.tsx (moveSnake, endGame, restart, mount/unmount)	moveSnake advances the snake, detects wall/self collisions, handles food consumption and scoring, endGame halts the tick and shows game-over, restart resets state; lifecycle hooks manage the interval.
Input handling and application bootstrap examples/snake-game/src/index.tsx (handleKey, main)	handleKey processes WASD/arrow keys with opposite-direction prevention, restart on r, quit on q or Ctrl+C; main() mounts the centered fullscreen App, wires key events, requests renders, and exits on quit.

Estimated Code Review Effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I hopped to the terminal, keys in paw,
A snake on the grid that I watched in awe,
Pellets to munch and walls to avoid,
Press r to retry when fate is deployed,
Play, quit, restart — a tiny bundle of joy.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	Description covers overview, features, technical implementation, and how to run. However, it lacks several required template sections: Related Issue link, Which package(s), Type of Change checkboxes, and Checklist items.	Complete the PR description with: explicit 'Closes #522' in Related Issue section, package identification (@termuijs/examples or similar), checked Type of Change box (Feature), and verification of all Checklist items.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	Title clearly and specifically summarizes the main change: adding a snake game example, which is the primary objective of the PR.
Linked Issues check	✅ Passed	PR implementation aligns with issue #522 requirements: creates snake-game example with Grid, movement, food, collision detection, restart on R, quit on Q/Ctrl+C, uses TermUI lifecycle methods, and includes proper config files.
Out of Scope Changes check	✅ Passed	All changes are confined to examples/snake-game/ directory. No modifications to packages/ or other areas outside scope. Changes include package.json, tsconfig.json, and index.tsx as specified.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[github-actions]

Hi @shaktipy 👋

⭐ Star this repo before your PR merges.

Why? GSSoC 2026 contributors who star get priority review and points credit. After you star, push any commit (or re-run this check). The needs-star label lifts automatically.

Thanks for your contribution to TermUI.

[github-actions]

🎉 Thanks for your first PR to TermUI, @shaktipy.

Before your PR merges:

1. ⭐ Star the repo. Required. The star-check job blocks your merge otherwise.
2. ✅ All checks green: build, test, typecheck.
3. 🏷 PR title follows type: short description. Example: fix: handle empty list.
4. 🔗 Link your closing issue in the description.

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• gssoc:approved. +50 base points.
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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@examples/snake-game/src/index.tsx`:
- Around line 96-105: The generateRandomFood() function can infinite-loop if the
snake fills the whole GRID_SIZE*GRID_SIZE board; update generateRandomFood to
first check if this.snake.length >= GRID_SIZE * GRID_SIZE and handle the "board
full" case by returning null (or throwing a clear BoardFullError) instead of
looping forever, change its return type to {x:number;y:number}|null (or keep
throwing) and then update callers (notably the food-spawn after eating in the
move/eat handler) to handle the null/board-full result by ending the game or
skipping spawning new food. Ensure references to generateRandomFood, the
food-spawn logic after eating, and the game-over/end-game handler are updated to
handle the new behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: f120a034-baae-4980-97a7-5e2324e169ec

📥 Commits

Reviewing files that changed from the base of the PR and between 142e1e3 and 5f0657f.

⛔ Files ignored due to path filters (1)

• bun.lock is excluded by !**/*.lock

📒 Files selected for processing (3)

• examples/snake-game/package.json
• examples/snake-game/src/index.tsx
• examples/snake-game/tsconfig.json