const assertion (as const) là gì?

as const biến values thành readonly literal types cụ thể nhất. Array thành readonly tuple, object properties thành readonly literal types.

Ví dụ: const dirs = ['left', 'right'] as const tạo type readonly ['left', 'right'] thay string[]. Hữu ích để tạo strongly-typed constants.

as const transforms values into the most specific readonly literal types. Arrays become readonly tuples, object properties become readonly literal types.

Example: const dirs = ['left', 'right'] as const creates type readonly ['left', 'right'] instead of string[]. Useful for creating strongly-typed constants.