Answers for "java «script know if exists an object with some atribute"

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

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

Check object property exists or not in js

const user1 = {
	username: "john"
};
const user2 = {
	username: "duo"
    authority: "grepper"
}
// check object property
console.log(user1.hasOwnProperty('authority')); // false
console.log(user2.hasOwnProperty('authority')); // true