I Can’t Believe This TS Feature Has No Documentation

TypeScript has an undocumented feature called const generics, which lets you add the `const` keyword before a generic type parameter. This automatically applies `as const` semantics to any value passed into the function, giving you the strictest possible literal type inference without requiring callers to manually append `as const` at every call site. The example demonstrates a generic `first()` function that, without const generics, infers a return type of `number` instead of the specific literal union `1 | 2 | 3`.