import { nextTestSetup } from 'e2e-utils'
import { retry } from 'next-test-utils'
import { computeCacheBustingSearchParam } from 'next/dist/shared/lib/router/utils/cache-busting-search-param'
describe('resume-data-cache', () => {
const { next, isNextDev } = nextTestSetup({
files: __dirname,
})
if (isNextDev) {
it('is skipped', () => {})
return
}
it.each([
{ name: 'use cache', id: 'random-number' },
{ name: 'fetch cache', id: 'another-random-number' },
])(
'should have consistent data between static and dynamic renders with $name',
async ({ id }) => {
// First render the page statically, getting the random number from the
// HTML.
let $ = await next.render$('/')
const first = $(`p#${id}`).text()
// Then get the Prefetch RSC and validate that it also contains the same
// random number.
await retry(async () => {
const url = new URL('/', 'http://localhost')
url.searchParams.set(
'_rsc',
await computeCacheBustingSearchParam(
'1',
'/__PAGE__',
undefined,
undefined
)
)
const rsc = await next
.fetch(url.toString(), {
headers: {
RSC: '1',
'Next-Router-Prefetch': '1',
'Next-Router-Segment-Prefetch': '/__PAGE__',
},
})
.then((res) => res.text())
expect(rsc).toContain(first)
})
// Then get the dynamic RSC and validate that it also contains the same
// random number.
await retry(async () => {
const rsc = await next
.fetch('/', {
headers: {
RSC: '1',
},
})
.then((res) => res.text())
expect(rsc).toContain(first)
})
// Then revalidate the page. Note: Dynamic RSC requests don't trigger
// actual revalidation - they only mark tags as needing revalidation.
// The actual revalidation only occurs when accessing a static resource again.
await next.fetch('/revalidate', { method: 'POST' })
// Then get the dynamic RSC again and validate that it still contains the
// same random number. The first request will get the stale data, but the
// second request will get the fresh data as it'll eventually have
// revalidated.
const rsc = await next
.fetch('/', {
headers: {
RSC: '1',
},
})
.then((res) => res.text())
expect(rsc).toContain(first)
// We then expect after the background revalidation has been completed,
// the dynamic RSC to get the fresh data.
await retry(async () => {
const rsc = await next
.fetch('/', {
headers: {
RSC: '1',
},
})
.then((res) => res.text())
expect(rsc).not.toContain(first)
})
// This proves that the dynamic RSC was able to use the resume data cache
// (RDC) from the static render to ensure that the data is consistent
// between the static and dynamic renders. Let's now try to render the
// page statically and see that the random number changes.
$ = await next.render$('/')
const random2 = $(`p#${id}`).text()
expect(random2).not.toBe(first)
// Then get the Prefetch RSC and validate that it also contains the new
// random number.
await retry(async () => {
const rsc = await next
.fetch('/', {
headers: {
RSC: '1',
'Next-Router-Prefetch': '1',
'Next-Router-Segment-Prefetch': '/__PAGE__',
},
})
.then((res) => res.text())
expect(rsc).toContain(random2)
})
// Then get the dynamic RSC again and validate that it also contains the
// new random number.
await retry(async () => {
const rsc = await next
.fetch('/', {
headers: {
RSC: '1',
},
})
.then((res) => res.text())
expect(rsc).toContain(random2)
})
// This proves that the dynamic RSC was able to use the resume data cache
// (RDC) from the static render to ensure that the data is consistent
// between the static and dynamic renders.
}
)
it('should use RDC for server action re-renders', async () => {
const browser = await next.browser('/server-action')
// Get the initial values
const initialCachedValue = await browser
.elementByCss('#cached-random')
.text()
const initialUncachedValue = await browser
.elementByCss('#uncached-random')
.text()
await browser.elementByCss('#refresh-button').click()
// Wait for the action to complete and verify:
// 1. The uncached value should change
// 2. The cached value should remain the same (proving RDC is being used)
await retry(async () => {
const cachedValueAfterAction = await browser
.elementByCss('#cached-random')
.text()
const uncachedValueAfterAction = await browser
.elementByCss('#uncached-random')
.text()
// Uncached value should have changed - this proves the action caused a re-render
expect(uncachedValueAfterAction).not.toBe(initialUncachedValue)
// Cached value should remain the same - this proves the RDC is being used
// to maintain consistency during server action re-renders
expect(cachedValueAfterAction).toBe(initialCachedValue)
})
})
it('should see fresh data after updateTag in server action with use cache', async () => {
// This test verifies that when a server action calls updateTag(),
// the subsequent re-render sees fresh data instead of stale RDC data.
// This is the "read your own writes" behavior for 'use cache'.
const browser = await next.browser('/revalidate-action')
// Get the initial cached value from the page render
const initialCachedValue = await browser
.elementByCss('#cached-value')
.text()
const initialUncachedValue = await browser
.elementByCss('#uncached-value')
.text()
// Click the revalidate button to trigger the server action
await browser.elementByCss('#revalidate-button').click()
// Wait for the re-render and verify:
// 1. The uncached value should change (proves re-render happened)
// 2. The cached value should ALSO change (proves updateTag was respected)
await retry(async () => {
const cachedValueAfterAction = await browser
.elementByCss('#cached-value')
.text()
const uncachedValueAfterAction = await browser
.elementByCss('#uncached-value')
.text()
// Uncached value should change - this proves the action triggered a re-render
expect(uncachedValueAfterAction).not.toBe(initialUncachedValue)
// Cached value should also change, which proves that the RDC read respected
// pendingRevalidatedTags and fetched fresh data instead of returning
// the stale value from the RDC.
// If this fails, it means the RDC is not respecting updateTag()
// calls made during server actions
expect(cachedValueAfterAction).not.toBe(initialCachedValue)
})
})
it('should see fresh data after updateTag in server action with fetch cache', async () => {
// This test verifies that when a server action calls updateTag(),
// the subsequent re-render sees fresh data instead of stale RDC data.
// This is the "read your own writes" behavior for fetch cache.
const browser = await next.browser('/revalidate-fetch-action')
// Get the initial cached value from the page render
const initialCachedValue = await browser
.elementByCss('#cached-value')
.text()
const initialUncachedValue = await browser
.elementByCss('#uncached-value')
.text()
// Click the revalidate button to trigger the server action
await browser.elementByCss('#revalidate-button').click()
// Wait for the re-render and verify:
// 1. The uncached value should change (proves re-render happened)
// 2. The cached value should ALSO change (proves updateTag was respected)
await retry(async () => {
const cachedValueAfterAction = await browser
.elementByCss('#cached-value')
.text()
const uncachedValueAfterAction = await browser
.elementByCss('#uncached-value')
.text()
// Uncached value should change - this proves the action triggered a re-render
expect(uncachedValueAfterAction).not.toBe(initialUncachedValue)
// Cached value should also change, which proves that the RDC read respected
// pendingRevalidatedTags and fetched fresh data instead of returning
// the stale value from the RDC.
// If this fails, it means the RDC is not respecting updateTag()
// calls made during server actions
expect(cachedValueAfterAction).not.toBe(initialCachedValue)
})
})
})