JavaScript · Language basics

Optional chaining

Stops evaluating and returns undefined when the value before ?. is null or undefined.

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Syntax

user?.address?.city

Example

Try it

const user = { name: "Ada" };
console.log(user.address?.city ?? "No city");

Do not use optional chaining to hide missing data you should handle explicitly.

Reference pages are the quick answer. The course explains the why, shows the full example and ends with a challenge.