The Nullish Coalescing Operator in JavaScript
The nullish coalescing operator (??) is a logical operator that returns its right-hand side operand when its left-hand side operand is nullish (null or undefined), and otherwise returns its left-hand side operand.
This can be seen as a special case of the logical OR (||) operator, which returns the right-hand side operand if the left operand is any falsy value, not only nullish.
Remember that a nullish value and a falsy value are different concepts. While null, undefined, 0, '', false, and NaN are considered falsy values, only null and undefined are considered nullish values.
Check the following code snippet:
Usage with the optional chaining operator (?.)
The nullish coalescing operator treats undefined and null as specific values and so does the optional chaining operator (?.) which is useful to access a property of an object which may be null or undefined.
Check the following code snippet:
Check browser compatibility: https://caniuse.com/mdn-javascript_operators_nullish_coalescing
About the author:
Miguel Munoz is a Principal Software Engineer here at Version 1.
