Run results for: in vs hasownproperty vs undefined

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36

Browser: Chrome 71

Operating system: Mac OS X 10.14.1

Device Platform: Desktop

Date tested: 5 years ago

Script Preparation code:

var obj = {
  x: 1,
  y: 1
}

Tests:

in
var t; if("x" in obj){ t = true; }else{ t = false; } var t2; if("l" in obj){ t1 = true; }else{ t1 = false; }
hasOwnProperty
var t; if(obj.hasOwnProperty("x")){ t = true; }else{ t = false; } var t2; if(obj.hasOwnProperty("l")){ t1 = true; }else{ t1 = false; }
undefined obj
var t; if(obj["x"]){ t = true; }else{ t = false; } var t2; if(obj["l"]){ t1 = true; }else{ t1 = false; }