Logical AND assignment (&&=)

The logical AND assignment (x &&= y) operator only assigns if x is truthy.

The logical AND operator is evaluated left to right, it is tested for possible short-circuit evaluation using the following rule:

(some falsy expression) && expr is short-circuit evaluated to the falsy expression;

Short circuit means that the expr part above is not evaluated, hence any side effects of doing so do not take effect (e.g., if expr is a function call, the calling never takes place).

Logical AND assignment short-circuits as well meaning that x &&= y is equivalent to:

x && (x = y);

And not equivalent to the following which would always perform an assignment:

x = x && y;

• Logical AND (&&)
• The nullish coalescing operator (??)
• Bitwise AND assignment (&=)
• Truthy
• Falsy