msw/test/browser/msw-api/hard-reload.test.ts

import { test, expect } from '../playwright.extend'

test('keeps the mocking enabled after hard-reload of the page', async ({
  loadExample,
  page,
  fetch,
  waitForMswActivation,
}) => {
  await loadExample(new URL('./hard-reload.mocks.ts', import.meta.url))

  page.evaluate(() => {
    /**
     * Emulate a forced reload.
     * Since `location.reload(true)` is deprecated, use a workaround.
     * @see https://stackoverflow.com/a/65544086/2754939
     */
    location.replace(location.href)
  })

  await waitForMswActivation()

  const res = await fetch('https://example.com/resource')
  const body = await res.json()

  // Still intercepts and mocks responses after a hard-reload.
  expect(res.fromServiceWorker()).toBe(true)
  expect(body).toEqual({ mocked: true })
})