deno-to-bun_skill

Overview

This skill helps migrate Deno projects to Bun by analyzing Deno.* API usage, converting configs, and recommending Bun equivalents. It produces a compatibility map, a migration checklist, and concrete code patterns to update imports, permissions assumptions, and test tooling. Use it to accelerate safe, repeatable migrations and to surface remaining manual steps.

How this skill works

The skill scans your project for Deno-specific APIs, import URLs, and deno.json/deno.jsonc settings, then maps each item to a Bun or Node equivalent. It suggests package.json and bunfig.toml entries, shows code replacements for common patterns (FS, HTTP, env, tests), and flags security-sensitive areas due to Bun's lack of a permission model. Finally, it outputs a verification checklist and recommended commands to validate the migration.

When to use it

• Converting a Deno project to Bun runtime
• Replacing Deno.* APIs with Bun/Node equivalents
• Migrating from Deno Deploy to Bun-compatible deployment
• Updating import maps and replacing URL imports with npm packages
• Adapting tests from Deno.test to bun:test

Best practices

• Run a pre-migration analysis to list Deno APIs and deno.json contents
• Replace URL imports with maintained npm packages or local files and add file extensions to imports
• Create package.json and bunfig.toml early to manage scripts and test preload
• Audit code for security risks because Bun has no permission system; prefer containers or secrets management
• Type-check with Bun’s tsc wrapper and run bun test before switching CI pipelines

Example use cases

• Convert a Deno HTTP server using Deno.serve to Bun.serve with minimal handler changes
• Replace Deno file I/O calls with Bun.file(...).text() and Bun.write(...) patterns
• Migrate tests from deno.land/std assertions to bun:test and update test scripts in package.json
• Translate deno.json tasks and imports into package.json scripts and dependencies, and generate tsconfig.json for Bun
• Prepare a Deno Deploy app for Bun by replacing platform-specific APIs and planning container deployment