How can I check for existence of an object property?

Question

I have variable that can be null, {}.

if (this.data) {
     this.postaddressForm.get('index_for').setValue(this.data.index_for);
     this.postaddressForm.get('dopaddr_for').setValue(this.data.dopaddr_for);
     this.postaddressForm.get('region_id').setValue(this.data.region_id);
     this.postaddressForm.get('house_for').setValue(this.data.house_for);
     this.postaddressForm.get('locality_for').setValue(this.data.locality_for);
     this.postaddressForm.get('street_for').setValue(this.data.street_for);
}

Problem is that sometimes there is properties in object data. How to check it?

So, if there is no street_for it fails.

Does this answer your question? https://stackoverflow.com/questions/45843668/optional-chaining-operator-in-typescript/58221278#58221278 — Sebastian Kaczmarek, Aug 14 '20 at 13:47

score 0 · Accepted Answer · answered Aug 14 '20 at 13:51

0

You can use || to set a default parameter, and .? to handle data being undefined:

this.data?.street_for || ""

answered Aug 14 '20 at 13:51

Luke Storry

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How can I check for existence of an object property?

1 Answers1