asUintN
BigInt.asUintN(4, 16n) // β 0n
16n exceeds 4-bit unsigned range (0-15) so it wraps to 0.
BigInt.asUintN(4, 16n) wraps to 0n because 16 equals 2^4.
BigInt.asUintN(4, 16n)
0n
Challenge: Verify this wrap.