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Object.defineProperty(Array.prototype, "0", {
  set: (v) => {
    throw new Error("WTF");
  },
});
console.log("Test");

Test
error: Uncaught Error: WTF
    throw new Error("WTF");
          ^
    at <anonymous> (file:///home/abotella/test.js:3:11)

I thought the array store in question in the above sample was in the console code, but it seems to happen when dealing with the load event:

Object.defineProperty(Array.prototype, "0", {
  get: () => {},
});

error: Uncaught TypeError: Cannot set property 0 of [object Array] which has only a getter
    at <anonymous> (deno:extensions/web/02_event.js:507:5)

Rather than primordials, this is related to naive property dereferencing vs using Object.hasOwnProperty()/ Object.getOwnProperty(). But even e.g. Array.prototype.join() is susceptible to Array.prototype[0] modification: The problem is entangled parts of our internal JS responding to that in less predictable ways. But it's hard to determine what is or isn't worth making more fault-tolerant if any of it.

It doesn't seem to be happening right now. Is this resolved?

% deno --version  
deno 1.40.4 (release, aarch64-apple-darwin)
v8 12.1.285.6
typescript 5.3.3