Heldinhow/deno-runtime

Deno Runtime

Overview

Deno is a secure TypeScript runtime built on V8, with built-in tooling and modern JavaScript features. This skill should be invoked when creating JavaScript/TypeScript applications that benefit from TypeScript-first development, built-in testing, and simplified dependency management.

Core Principles

• TypeScript First: Use TypeScript natively without compilation setup
• URL Imports: Import dependencies directly from URLs
• Security by Default: Explicit permissions for file, network, environment access
• Built-in Tools: Use Deno for linting, formatting, testing, and bundling

Preparation Checklist

• [ ] Install Deno: curl -fsSL https://deno.land/x/install/install.sh | sh
• [ ] Verify installation: deno --version
• [ ] Review Deno API differences from Node.js
• [ ] Set up editor (VS Code with Deno extension)

Step-by-Step Process

1. Initialize: Create TypeScript files directly
2. Import: Use URL imports for dependencies
3. Write Code: Leverage TypeScript and Deno APIs
4. Run: Execute with deno run --allow-<perm> <file.ts>
5. Test: Use deno test for test suites
6. Deploy: Deploy to Deno Deploy or Deno-compatible platforms

Do's and Don'ts

• ✅ Do use explicit permissions flags (--allow-read, --allow-net)
• ✅ Do use Deno's built-in formatting: deno fmt
• ✅ Do use Deno's linter: deno lint
• ❌ Don't assume all Node.js packages work
• ❌ Don't use require() - use ES modules only
• ❌ Don't skip permission flags in production

Anti-Patterns

• Node Assumption: Assuming Node.js APIs work identically
• Missing Permissions: Running without required permissions
• NPM Packages: Trying to use npm packages without compatibility layer
• Ignoring Security: Not using Deno's permission system