//Look at the other comments but heres a way I made it more simple
Object.prototype.keys=function(){return Object.keys(this);}
//you might see that im trying to make it short and comment use arrow functions.
//but arrow functions actually have diffrent abilites. see what happens.
const obj = {
foo:"bar",
bar:"foo"
}
console.log(obj.keys()); //["foo", "bar"]
Object.defineProperty(Object.prototype, "keys", { //more simpler to use
get:function(){return Object.keys(this);}
});
console.log(obj.keys); //["foo", "bar"]