What is the nullish coalescing operator?

The nullish coalescing operator (??) in JavaScript returns an alternative value only when the given value is considered null or undefined.

let result = value1 ?? value2

If value1 is null or undefined, value2 is returned. Otherwise, value1 is returned.

Here are some clearer examples:

A default message like "No data":

let result = value ?? 'No data'

If value is null or undefined, "No data" is returned.

A default numeric value:

let pageNumber = currentPage ?? 1

If currentPage is null or undefined, 1 is returned.

A default object:

let settings = userSettings ?? { theme: 'dark', fontSize: 14 }

If userSettings is null or undefined, the default settings object is returned.