The JavaScript double question mark operator (??) is a logical operator that returns the first operand if it is truthy, and the second operand if it is falsy. It is often used to provide a default value for a variable or to check if a variable is null or undefined.
The double question mark operator is a powerful tool that can be used to improve the readability and maintainability of your code. It can also help to prevent errors by ensuring that variables are always assigned a valid value.