The Power of TypeScript's Satisfies Operator - snippet-4.ts

snippet-4.ts

type Route = {
  path: string
  method: 'GET' | 'POST' | 'PUT' | 'DELETE'
}

const routes = {
  users: { path: '/api/users', method: 'GET' },
  createUser: { path: '/api/users', method: 'POST' },
  updateUser: { path: '/api/users/:id', method: 'PUT' },
} satisfies Record<string, Route>

// TypeScript knows exactly what routes exist
routes.users.method // Type is 'GET', not 'GET' | 'POST' | 'PUT' | 'DELETE'
routes.nonexistent // Error! Caught at compile time