Run results for: typeof vs undefined

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36

Browser: Chrome 80

Operating system: Mac OS X 10.15.4

Device Platform: Desktop

Date tested: 4 years ago

Script Preparation code:

var x;
var und = 'unde';
und += 'fined'

Tests: