Eamon Hyland's Preferences

Category	Preference
Package Manager	Bun for apps, pnpm for libraries
Language	TypeScript (strict mode, ESM only)
Linting & Formatting	Oxlint and Oxfmt
Testing	Bun for apps, Vitest for libraries
Git Hooks	simple-git-hooks + lint-staged
Bundler	Bun for apps, tsdown for libraries

Core Conventions

Server environment configuration

Server configuration should be loaded from environment variables and validated with zod
Default values should be set for dev environment
Test defaults can be set in the test runner (e.g. bun test or vitest setup script)

Configuration should be defined in

src/config.ts

src/server/config.ts

(for fullstack apps)

// src/config.ts
import { z } from "zod";

const configSchema = z.object({
  PORT: z.coerce.number().default(3000),
  NODE_ENV: z.enum(["development", "production", "test"]).default("development"),
  DATABASE_URL: z.string().default("sqlite.db"),
});

const parsed = configSchema.safeParse(process.env);

if (!parsed.success) {
  console.error("❌ Invalid environment variables:", parsed.error.flatten().fieldErrors);
  process.exit(1);
}

export const config = parsed.data

// src/config.ts
import { z } from "zod";

const configSchema = z.object({
  PORT: z.coerce.number().default(3000),
  NODE_ENV: z.enum(["development", "production", "test"]).default("development"),
  DATABASE_URL: z.string().default("sqlite.db"),
});

const parsed = configSchema.safeParse(process.env);

if (!parsed.success) {
  console.error("❌ Invalid environment variables:", parsed.error.flatten().fieldErrors);
  process.exit(1);
}

export const config = parsed.data

// src/test/setup.ts
process.env.DATABASE_URL = ":memory:";

client -> server communication

Prefer trpc with react query for fullstack projects (when the server and client are in the same package). See bun-trpc-setup.
Otherwise prefer graphql. See bun-graphql-setup.

TypeScript

Never use
```
@ts-ignore
```
Never use
```
as any
```
casting or
```
as unknown as <some-other-type>
```

Preferred

tsconfig.json

config

json

{
  "compilerOptions": {
    "target": "ESNext",
    "module": "ESNext",
    "moduleResolution": "bundler",
    "strict": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": true,
    "noImplicitReturns": true,
    "noUncheckedIndexedAccess": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true
  }
}

Package.json scripts

The following are my preferred set of package.json scripts. Not all scripts are relevant to all projects e.g. library packages will not have db scripts

jsonc

{
  "scripts": {
    "dev": "bun run --watch src/index.ts",
    
    "db:generate": "drizzle-kit generate",
    "db:studio": "drizzle-kit studio",
    
    "typecheck": "tsc --noEmit",
    
    "format": "oxfmt src",
    "format:check": "oxfmt src --check",

    "lint": "oxlint --type-aware",
    "lint:fix": "oxlint --type-aware --fix --fix-suggestions --fix-dangerously",

    "fix": "bun format && bun lint:fix",

    "check": "concurrently 'bun:format' 'bun:lint:fix' 'bun:typecheck' 'bun:test' 'bun:test:e2e'",
    
    "test": "bun test",
    "test:e2e": "playwright test"
  }
}

Linting Setup

Use Oxlint and Oxfmt from OXC

json

// .oxlintrc.json
{
  "$schema": "./node_modules/oxlint/configuration_schema.json",
  "plugins": ["typescript"],
  "rules": {
    "typescript/no-floating-promises": "error",
    "typescript/no-unsafe-assignment": "warn"
  }
}

json

// .oxfmtrc.json
{
  "$schema": "./node_modules/oxfmt/configuration_schema.json",
  "trailingComma": "all",
  "printWidth": 80,
  "ignorePatterns": []
}

Fix linting errors & formatting errors with fix script, e.g.

bun run fix

pnpm run fix

Git Hooks

Use npm dependencies

simple-git-hooks

lint-staged

json

{
  "simple-git-hooks": {
    "pre-commit": "pnpm i --frozen-lockfile --ignore-scripts --offline && pnpm lint-staged"
  },
  "lint-staged": { "*": "pnpm fix" },
  "scripts": { "prepare": "pnpm simple-git-hooks" }
}

Test Conventions

Test files:
```
foo.ts
```
→
```
foo.test.ts
```
(same directory)
Use
```
describe
```
/
```
it
```
API (not
```
test
```
)

References

Topic	Description	Reference
Bun and tRPC Setup	Configuration for Bun.serve with native routes and tRPC fetch adapter	bun-trpc-setup
Bun and GraphQL Setup	Configuration for Bun.serve with Yoga GraphQL	bun-graphql-setup
SQLite with Drizzle	SQLite setup with Drizzle ORM in Bun runtime, schema, migrations, testing	sqlite-drizzle
Deployment and CI/CD Setup	Buildkite pipelines, docker configuration	deployment

ehyland

NPX Install

Tags

SKILL.md Content

Eamon Hyland's Preferences

Core Conventions

Server environment configuration

client -> server communication

TypeScript

Package.json scripts

Linting Setup

Git Hooks

Test Conventions

References