typescript-advanced-types

Define an event map type mapping event names to payload types, then use a generic class with mapped types for the listeners record. The `on` and `emit` methods constrain event names with `keyof T` so payloads are checked at compile time.

Use conditional types with the `infer` keyword, such as `T extends (...args: infer P) => infer R`. TypeScript also ships built-in `ReturnType<T>` and `Parameters<T>` utility types for the same purpose.

Interfaces are preferred for object shapes because they produce better error messages and support declaration merging. Type aliases are more flexible for unions, conditional types, mapped types, and other complex type computations.

Yes, enabling strict mode is recommended because strict null checks and related flags make conditional types and type guards behave correctly. Without it, patterns like NonNullable and discriminated union narrowing lose their safety guarantees.

Deeply nested or recursive conditional types force the compiler to evaluate many type instantiations, increasing check time. Mitigate this by caching computed types in aliases, limiting recursion depth, and preferring simpler types where possible.

Use `unknown` for values whose type is not yet determined, because it forces type narrowing through guards before use. The `any` type disables all checking and defeats the purpose of TypeScript's type safety.