Function extend

packages/browser/src/client/tester/context.ts:428–433

(methods)

    throw new Error(`Method class="st">"frameLocator" is not supported by the class="st">"${provider}" provider.`)
  },
  extend(methods) {
    for (const key in methods) {
      (page as any)[key] = (methods as any)[key].bind(page)
    }
    return page
  },
}

function convertToLocator(element: Element | Locator): Locator {