pzuraq/proxy-issue.md

## proxy-issue.md

      
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              proxy-issue.md
            
          
    class Foo {
  @tracked bar;

  get baz() {
    return this.bar;
  }
}

let foo = new Foo();
In order to make this work, we need to know that bar is a dependency of baz
when we access foo.baz. Currently, we know this because bar is instrumented.
In order to know this with proxies, we must not only wrap foo in a proxy, we
must recursively wrap it in a proxy. Otherwise, baz is a black box, we have
no idea what it accessed:
class Foo {
  bar;

  get baz() {
    return this.bar;
  }
}

let foo = new Foo();
let proxy = new Proxy(foo, {
  get(target, key) {
    let getter = Object.getOwnPropertyDescriptor(foo, key).get;

    return get.call(proxy);
  }
});
Every access to this must be watched, even internally. Now, if we add a
private field internally, we break:
class Foo {
  #bar;

  get baz() {
    return this.#bar;
  }
}

let foo = new Foo();
let proxy = new Proxy(foo, {
  get(target, key) {
    let getter = Object.getOwnPropertyDescriptor(foo, key).get;

    return get.call(proxy);
  }
});

foo.baz; // ERROR