javascript objext has code example

Example 1: js check if object has property

const object1 = new Object();
object1.property1 = 42;

console.log(object1.hasOwnProperty('property1'));
// expected output: true

Example 2: how reliable is js hasownproperty

o = new Object();
o.propOne = null;
o.hasOwnProperty('propOne');   // returns true
o.propTwo = undefined;  
o.hasOwnProperty('propTwo');   // returns true