Javascript optional chaining operator (?.)

Fri Nov 06 2020

Have you ever found yourself having to write something like:

if ('user' in data && 'job' in data.user && data.user.job.name == 'Peter')

An endless if 'y' in z && z in x.y.z ...?

The Optional chaining (?.) (opens new window) operator is here to save you!

With the optional chaining operator you can simply do:

if (data?.user?.job?.name == 'Peter')

?. returns undefined if any of the properties (or functions in the case of function calls) don't exist.

It can be used together with the nullish coalescing operator (??) (opens new window) to return default values:

let name = data?.user?.job?.name ?? 'Default name';