how to intercept "in" operator in javascript?

Question

I have an object, i want to intercept in opeartor access on the object.

e.g

myObject.operatorIn = ()=>throw new Error("You can't touch it :)")

Answer 1

With a Proxy, you can create a has trap to intercept uses of in:

const myObject = {
  foo: 'foo'
};
const myObjectProxy = new Proxy(
  myObject,
  {
    has() {
      throw new Error("You can't touch it");
    }
  }
);
console.log(myObjectProxy.foo);
console.log('foo' in myObjectProxy);