Logical assignment operators in JavaScript: small syntax, big wins - Matt Smith
In day-to-day JavaScript, we often write code that checks a variable before assigning it a new value. These checks can get repetitive, especially when working with component props, global configs, or state objects. That’s where logical assignment operators come in, a compact ES2021 feature that simplifies common conditional assignments without changing the underlying logic.
Logical assignment operators combine a logical operator (||, &&, or ??) with assignment (=) to create a shorthand form. These operators also short-circuit like regular logical expressions, meaning the right-hand side is only evaluated if the left-hand side fails the logical test (i.e., is falsy, truthy, or nullish).
Optional chaining returns the result of a property access, not a reference to the property itself. Since assignment targets must be references (i.e., a variable or object property), this isn’t valid JavaScript.
This is useful for setting a default if a value hasn’t been initialized. But it overwrites values like 0, '', or false, which might be intentionally set.
