按位與賦值 (&=)

let a = 5; // 00000000000000000000000000000101
a &= 3; // 00000000000000000000000000000011

console.log(a); // 00000000000000000000000000000001
// Expected output: 1

x &= y

let a = 5;
// 5:     00000000000000000000000000000101
// 2:     00000000000000000000000000000010
a &= 2; // 0

let b = 5n;
b &= 2n; // 0n