Like the title
I don’t want to use jquery’s getOwnPropertyNames

var getProperty = function(obj) { var nArr = []; for (var i in obj) { nArr.push[i]; } console.log(nArr); return nArr; } getProperty({a:1,b:2})

The final result returned is [];
if changed to

var getProperty = function(obj) { var nArr = [], k = 0; for (var i in obj) { nArr[k] = i; k++; } console.log(nArr); return nArr; } getProperty({a:1,b:2});

The correct result can be returned ['a','b'], why