In JavaScript, the double query mark (??) is a logical operator that evaluates its left operand and returns its proper operand provided that the left operand is null or undefined. This operator is usually used as a alternative for the ternary conditional operator (?:) when the purpose is to supply a default worth for a variable or property.
The double query mark operator is especially helpful in conditions the place the left operand could also be undefined or null as a consequence of asynchronous operations or exterior elements. Through the use of the ?? operator, you possibly can be sure that a default worth is at all times returned, stopping errors and making certain the graceful execution of your code.