How to check if a "deep" structure is not undefined?

Question

what is the best aproach to check if a "deep" structure is undefined?

For example I have some check like this:

if (json.error.message != undefined) {
    console.log(json.error.message);
}

The problem here is, that if json.error is already undefined this will crash. So I would need to write something like:

if (json.error != undefined && json.error.message != undefined) {
    console.log(json.error.message);
}

But this could not be the best aproach or? When I would have even "deeper" structures.

[Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?](https://stackoverflow.com/q/6613952/102937) — Robert Harvey, Jan 14 '21 at 19:56
Check this article about `Elvis` operator aka safe navigation operator.https://www.beyondjava.net/elvis-operator-aka-safe-navigation-javascript-typescript — Mu-Majid, Jan 14 '21 at 20:02

score 1 · Accepted Answer · answered Jan 14 '21 at 20:05

1

if (json?.error?.message != undefined) {
    console.log(json.error.message);
}

answered Jan 14 '21 at 20:05

novarx

1 Answers1