Declaration File

Definitions

1. A TypeScript file with a .d.ts extension that provides type information for JavaScript code without containing implementation. Declaration files enable IDE autocompletion and type checking for untyped JS libraries. DefinitelyTyped hosts community-maintained declarations for thousands of packages.

   In plain English: A file that describes the shape and types of a JavaScript library so TypeScript can check your code for mistakes without rewriting the library.

Related Terms

• Discriminated Union
• Generics
• Type Guard
• Union Type
• Utility Types
• Structural Typing
• Hot Reload
• Debug Build
• Partial Type
• Type Declaration
• Type Definition
• Type Predicate
• Zod
• Complex Type