Operators — &&=, ||=, ??= logical assignment

Logical assignment operators (ES2021)

• a &&= b — assigns b only if a is truthy
• a ||= b — assigns b only if a is falsy
• a ??= b — assigns b only if a is null/undefined

Challenge: Write logicalAssignment() that:

1. let a = 1; a &&= 99 → return a
2. let b = 0; b ||= 42 → return b
3. let c = null; c ??= 'hello' → return c