use Optional Chaining to check for null or undefined

Question

I'm using this code

data?.response[0]?.Transaction[0]?.UID;

here Transaction key is not available, i'm getting

ERROR TypeError: Cannot read properties of undefined (reading '0')

I was trying to check for null or undefined using Optional Chaining rather than checking it with if.

Can you provide a sample blueprint of the object you're working with? — Haneen Mahdin, Dec 14 '22 at 14:32

score 1 · Accepted Answer · answered Dec 14 '22 at 14:33

1

Optional chaining works for array indexes too:

data?.response?.[0]?.Transaction?.[0]?.UID

For example:

const obj = {
  arr: [1]
};

console.log('exists:', obj?.arr?.[0]);
console.log('does not exist:', obj?.another_arr?.[0]);

answered Dec 14 '22 at 14:33

David

1 Answers1