Function overlayProxy

packages/shared/src/proxy.ts:62–83

(
  target: Value<T>,
  partial: U,
)

 * Useful when you want to override or extend behavior without fully copying/merging objects.
 */
export function overlayProxy<T extends object, U extends object>(
  target: Value<T>,
  partial: U,
): U & Omit<T, keyof U> {
  const proxy = new Proxy(typeof target === 'function' ? partial : target, {
    get(_, prop) {
      const targetValue = prop in partial
        ? partial
        : value(target)

      const v = Reflect.get(targetValue, prop)
      return typeof v === 'function'
        ? v.bind(targetValue) // .bind is required for async generator or iterator
        : v
    },
    has(_, prop) {
      return Reflect.has(partial, prop) || Reflect.has(value(target), prop)
    },
  })

  return proxy as any
}