satisfies operator

The `satisfies` operator checks that an expression conforms to a target type while preserving the expression's inferred type. It helps configuration objects, route maps, theme tokens, and lookup tables where you want validation without losing literal detail.

					const routes = {
  api: { path: '/v1' },
  admin: { path: '/admin' },
} satisfies Record<string, { path: string }>;
				

Compare with annotation (may widen), assertion (unsafe), and `as const` (no external shape check). `satisfies` does not change runtime behavior.

On interviews: explain with a concrete example and name what interviewers probe in production code.

Common pitfalls: mixing similar APIs and forgetting edge cases during live coding.

The trade-off is often clarity versus safety or expressiveness versus maintainability. Checklist:

• Use for config objects.
• Preserve literals.
• Remember compile-time only.