contextBridge.exposeInMainWorld: prototype loss and origin‑agnostic access

Goal

Expose a class instance from a preload script to the renderer using contextBridge.exposeInMainWorld while retaining its prototype methods and restricting calls to the current origin.

Constraints

• The bridge performs a shallow, enumerable own‑property copy; prototype methods, getters, setters, and non‑enumerable properties are omitted.
• Values are structured‑cloned, so class instances arrive as plain objects and instanceof checks fail.
• Electron provides no built‑in per‑origin or per‑window permission boundary for exposed APIs; any renderer in the session can invoke them.

Unresolved Questions

1. What mechanism can preserve a class’s prototype chain when exposing it via contextBridge?
2. Is there a configuration or API to enforce per‑origin or per‑window access control on exposed methods?
3. Which Electron releases introduced the prototype‑loss behavior, and are there pending fixes?