TypeScript satisfies operator for type-safe object literals

// Problem: 'as const' loses type checking
const config = {
  endpoint: 'https://api.example.com',
  timeout: 'not-a-number',  // BUG: should be number, but no error
} as const;

// Problem: explicit type annotation loses literal types
type Config = { endpoint: string; timeout: number };
const config2: Config = {
  endpoint: 'https://api.example.com',
  timeout: 5000,
};
// config2.endpoint is typed as 'string', not 'https://api.example.com'

// SOLUTION: satisfies
const config3 = {
  endpoint: 'https://api.example.com',
  timeout: 5000,
} satisfies Config;
// config3.endpoint is typed as 'https://api.example.com' (literal!)
// config3.timeout is typed as 5000 (literal!)
// AND: type checking is enforced at definition

// Real use case: route configuration
type Route = {
  path: string;
  handler: string;
  methods: ('GET' | 'POST' | 'PUT' | 'DELETE')[];
  requiresAuth: boolean;
};

const ROUTES = {
  traces: {
    path: '/api/v1/traces',
    handler: 'tracesRouter',
    methods: ['GET', 'POST'],
    requiresAuth: true,
  },
  search: {
    path: '/api/v1/traces/search',
    handler: 'searchRouter',
    methods: ['POST'],
    requiresAuth: false,
  },
} satisfies Record<string, Route>;

// TypeScript knows exact types:
// ROUTES.traces.methods is ('GET' | 'POST')[], not ('GET'|'POST'|'PUT'|'DELETE')[]
// ROUTES.search.requiresAuth is false, not boolean

// Useful for CSS-in-JS / theme objects
type ThemeColors = Record<string, `#${string}` | `rgb(${string})` | 'transparent'>;
const colors = {
  primary: '#3B82F6',
  secondary: '#6B7280',
  danger: '#EF4444',
} satisfies ThemeColors;
// colors.primary is typed as '#3B82F6', enables autocomplete and refactoring