How does Astro handle TypeScript and type safety?

Astro has first-class TypeScript support with zero configuration needed. Type Astro components: interface Props { title: string; date: Date; optional?: boolean; } const { title, date, optional = false } = Astro.props;. TypeScript is checked during astro check and in IDEs. Content collections: the Zod schema defines TypeScript types automatically — frontmatter properties are fully typed. Astro types: import from astro: import type { APIRoute, MarkdownInstance, GetStaticPaths } from 'astro'. Framework components: React/Vue/Svelte components retain their TypeScript types when used in Astro. Env variables: SITE_URL defined in astro.config's env.schema is fully typed. Strict mode: Astro's tsconfig extends tsconfig/strictest for maximum type safety. astro check validates TypeScript in .astro files in addition to .ts/.tsx. Run in CI to catch type errors before deployment.