Run results for: typeof vs undefined

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 15

Operating system: iOS 15.4.1

Device Platform: Mobile

Date tested: one year ago

Script Preparation code:

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

Tests: