const object1 = {
  property1: 42
};
Object.seal(object1)
const object2 = object1;
object2.property1 = 33;
object2.property2 = 11;
console.log(object1.property1); // 33
console.log(object1.property2); // undefined
console.log(Object.isSealed(object1)); // true
console.log(object2.property2); // undefined

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