How to test if an object is a Proxy?

Question

I would like to test if a JavaScript object is a Proxy. The trivial approach

if (obj instanceof Proxy) ...

doesn\'t work here, nor does tra

Answer 1

Create a new symbol:

let isProxy = Symbol("isProxy")

Inside the get method of your proxy handler you can check if the key is your symbol and then return true:

get(target, key)
{
    if (key === isProxy)
        return true;

    // normal get handler code here
}

You can then check if an object is one of your proxies by using the following code:

if (myObject[isProxy]) ...