How to check if property exists on potentially undefined object? [duplicate]

Answer 1

if you want to check both obj and prop exists (like you mentioned in your comments) you have to do:

if(obj && obj.hasOwnProperty('some')) or if(obj && obj.some)

As mentioned in comments this will throw error if obj is undefined. A better comparison would be would be:

if(typeof obj != "undefined" && obj.hasOwnProperty('some'))