how to know if some property value is in an object code example

Example 1: how to check wether the property exist in a object in java script

if (obj.hasOwnProperty('prop')) {
    // do something
}

Example 2: js check if object has property

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

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