• Typing default export
• Typing function
• Type Buddy
• Are the types wrong?
• Project References & You might not need TypeScript project references
• TypeScript Twoslash
• Method Shorthand Syntax Considered Harmful

Library

• @sindresorhus/is (type-check)
• ts-extras
• ts-pattern (pattern matching)

Schema validation

• Standard Schema

• zod
• ArkType
• Valibot
• effect/Schema

Type-only

• type-fest
  • Branded type: Tagged