Bitwise AND assignment (&=)

The bitwise AND assignment operator (&=) uses the binary representation of both operands, does a bitwise AND operation on them and assigns the result to the variable.

Operator: x &= y
Meaning:  x  = x & y

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

• Assignment operators in the JS guide
• Bitwise AND operator