Hint
Own properties shadow prototype properties. The prototype is consulted only for missing own properties.
const proto = { x: 1, y: 2 };
const obj = Object.create(proto);
obj.x = 10;
console.log(obj.x);
console.log(obj.y);
console.log(obj.hasOwnProperty('y'));10 2 false
Explanation: obj.x=10 shadows proto.x=1. y is not on obj, found on proto. hasOwnProperty("y") is false.
Key Insight: Own properties shadow prototype properties. The prototype is consulted only for missing own properties.