[Javascript] Intercept property access with Javascript Proxy

A Javascript Proxy object is a very interesting es6 feature, that allows you to determine behaviors whenever a property is accessed in a target object. In this lesson, you will learn how to use it to prevent users from accessing specific properties in your objects

 

test("Intercept property access using es6 Proxies", () => {
  const obj = {
    _id: "klsjdahflkastfaskfdg",
    name: "Khaled"
  };
  const handler = {
    get: (target, prop) => {
      if (prop[0] === "_") {
        throw new TypeError("Access denied");
      }
      return target[prop];
    },
    set: (target, prop, value) => {
      if (prop[0] === "_") {
        throw new TypeError("Access denied");
      }
      target[prop] = value;
      return true;
    }
  };
  const proxy = new Proxy(obj, handler);

  expect(() => {
    proxy._id;
  }).toThrow();
  expect(() => {
    proxy._id = "something";
  }).toThrow();
});