I am parsing a complex object in Typescript, so have something like:
const a = reply['price']['value']['total']['value'];
and I like to ensure that all elements are defined in the chain, otherwise, it should set a=0 and do not trigger an exception if some of the chained keys are in fact undefined.
What would be the appropriate syntax for that?
>Solution :
If you’re using modern JS you can use nullish coalescing and optional chaining
const a = reply?.['price']?.['value']?.['total']?.['value'] ?? 0;
Try to avoid using || instead of ??, because that will give you 0, if the final value is any falsy value, like 0 or false.
If you don’t want to use nullish coalescing, you can do this, which achieves the same.
const a = reply?.['price']?.['value']?.['total']?.['value'] ? reply['price']['value']['total']['value'] : 0;