Fixes #9284

* Polyfilling fetch and object-assign

* Polyfilling corejs object-assign

* Adding object-assign in polyfills.js. IE11 does not support Object.assign

* Fixing failing test

* Updating object.assign polyfill to fix aliasing

* Updating test case value to match new build stats

* Increasing the size of default build to 225kb

* Fixing defer-script test case to not include polyfill.js

* Revert README.md

* Re-design the polyfill approach based on PR feedback

* Adding comment and fixing test case

* Rename polyfills chunk

* Extract aliases into helper

* Remove extra new line

* Fix TypeScript typings

* Adding _internal_fetch alias

* Adjust build manifest plugin

* Build manifest plugin changes - adding a separate entry for polyfills

* Rename polyfills entry in build-manifest.json

* Remove old comment

* Fix TS

* Set key

* Polyfills already added

* Filtring polyfill.module.js

* Fix test

* Add __internal_fetch to alias rule

* Adjust name

* bump size

* ignore polyfills

* sigh

* Disallow iSSG revalidation period of zero

* Fix revalidation period in test

* Add initial bit for plugins

* Add checks for needed metadata values

* Add test

* Initial plugins changes

* Add handling for _app middleware

* Add loading of _document middleware and
handling of multiple default export syntaxes

* Fix insert order for middleware member expression

* Remove early return from middleware plugin from testing

* Add tests for current plugin middlewares

* Update test plugin package.json

* Update handling for class default export

* Update to use webpack loader instead of babel
plugin, remove redundant middleware naming, and add field for required env for plugins

* Add middleware to support material-ui use case
and example material-ui plugin

* Update tests and remove tests stuff from google analytics plugin

* Remove old plugin suite

* Add init-server middleware

* Exit hard without stack trace when error in collecting plugins

* Add on-error-client and on-error-server and update
to run init-server with next-start in serverless mode

* Update init-client for google analytics plugin

* Add example Sentry plugin and update with-sentry-simple

* Remove middleware field/folder and use src dir for plugins

* Add post-hydration middleware and update
material-ui plugin

* Put plugins code behind flag

* Update chromedriver

* Revert "Update chromedriver"

This reverts commit 1461e978e677f7da05e29e0415ec614a04bf65f9.

* Update lock file

* Remove un-needed _app for sentry example

* Add auto loading of scoped packages, add plugins
config for manually listing plugins, and update
to only collect plugins once

* Update example plugins

* Expose plugins' config

* Rename plugin lifecycles and add babel-preset-build

* Rename other methods with unstable

* Update log when plugin config overrides auto-detecting

* Don't rely on page-config plugin to detect iSSG usage

* Make sure to only update sprStatus if page file

* Remove dead-code elimination for iSSG code

* Revert next-page-config.ts

* Update index.js

* Update index.test.js

* Add experimental config for React Mode

* Use latest types

* Use latest types

* Throw Error for next.config.ts

Ref: https://github.com/zeit/next-plugins/issues/555

* Check for .js else .ts

* Update Error Message
Co-Authored-By: NAlexander Kachkaev <alexander@kachkaev.ru>

* Add test case when both next.config.js and next.config.ts exist.

* Remove extra constant CONFIG_FILE_TS and Add check for ts/tsx/json

* Rename test config parameter and add tsx and json files

* Change messege

* change value

* Update next.config.json

* Update next.config.json

* Change message  and add jsx filter

* Adjust

* Simplify test

* adjust

* Update to use a historyId to track invalid popstates

* Remove log from debugging

* Use Math.random instead of Date.getTime to avoid mocks

* Pass config.experimental.cpus to export during build

Currently, there is no way of specifying the number of worker threads of
`next export` when run as part of `next build`.

I suggest a sane default should be to just use the same amount of
workers that were used during the build process which currently seems to
be configured through `config.experimental.cpus`.

This setting is already respected in the two other places where
jest-workers are in use: The TerserPlugin and the staticCheckWorkers in
`next build`.

* Only enable worker threads if there is more than 1 worker

Multiple worker threads can cause problems when certain dependencies are
being used, see e.g. https://github.com/zeit/next.js/issues/7894

This patch allows disabling of worker threads by setting
`config.experimental.cpus = 1`.

The benefit of spawning 1 worker thread, if there is any at all, should
very limited anyways, so the workload can just as well be processed in
the main thread.

* Disable parallel build for firebase authentication example

* Add integration test to cover #7894

* Rename test suite and add worker_threads config

* Disable worker_threads by default

* Update index.test.js

* Use workerThreads config for TerserPlugin

* Update to use workerThreads config in
TerserPlugin for consistency

* Disable node 12 specific test

* Add warning for getStaticParams without getStaticProps

* Throw error instead of logging to make sure it's noticed

* Lower default concurrency for tests

* Take multiple values into account

* make typescript happy

* allow NextScript to optionally defer javascript

* move defer options to experimental feature

* combine defer flags into a single option

* Update deferScripts to work with serverless target

* Add test for defer and async property

* Read the async property

* Check versions of chrome and chromedriver

* Update to chromedriver 76

* Fix test

* Add StrictMode toggle

* Rename option to reactStrictMode

* Default to false initially

* Ensure directory before flushing cache iSSG file

* Add test for prerender cache flush

* Nest the dynamic route test one more level

* update fetch for test

* Update error check

* Cache No-Revalidate Pages

* Specifically check for `false`

* Dedupe meta tag in favor of custom tag defined in _app

* Add test

* Fix comments

* Don't mark page as nextExport if it's SPR

* Add test for fetching prerender data after mount

* Add failing tests for SPR

* Fix SPR always revalidating in production

* Remove extra changes

* Update to error on usage of serverRuntimeConfig with serverless

* Add tests for errors for serverless and runtime configs

* Update docs wording

* Add buildId to SPR data routes

* Update buildId replace in serverless loader

* Use new RegExp and add comment

* Apply suggestions from code review
Co-Authored-By: NJoe Haddad <joe.haddad@zeit.co>

* Test to ensure client transition and handle / data route

* Test `public/static/` folder

* Public routes should be matched before static catch-all

* Remove experimental.publicDirectory config

* Error when public is set as an output dir

* Remove experimental.publicDirectory checks

* Update publicFiles checking in next build

* Convert Dev Server to TypeScript
This converts the Next.js Development Server to TypeScript in prep for upcoming changes.

* Convert remaining necessary

* Fix some type errors

* Adjust types

This pull request converts Next.js' export CLI command to use TypeScript. This is useful for upcoming changes.

* s/Automatic Prerendering/Automatic Static Optimization/

* Update more links

* Add new `srcRoute` attribute to SprRoute

* Update prerender manfiest test snapshot

* Fix types

* Update Prerender Manifest

* Fix typescript

* Add SPR Dynamic Routes to Manifest
This adds dynamic routes for SPR pages to the prerender manifest so we can configure the Now Builder to handle these routes as SPR routes. Otherwise, they're treated like normal `getInitialProps` pages.

* Fix types

* Configure the Default Revalidate
The default revalidate behavior should be configured by Next.js. Otherwise, the behavior might drift or change in non-semver compliant ways between Next.js and the builder (or other 3rd party setups).

* Add additional comment

Per the HTTP specification, only natural numbers may be used for caching durations. We should enforce this with a really helpful error message.

The Now CDN does not support the `stale-if-error` header and already behaves like that for `stale-while-revalidate`.

Removing this header allows Now CDN to use its default headers instead of sending _only_ `stale-if-error` after stripping `s-maxage` and `stale-while-revalidate`.

* Add revalidate header and error when invalid
object from getStaticProps

* Make sprCache no-op in dev mode

* Update packages/next/next-server/server/next-server.ts

* Update tests for fixes

* Update getStaticProps error and add test

* Update manifest test

* Add validating revalidate value

* Apply suggestions from code review
Co-Authored-By: NJoe Haddad <joe.haddad@zeit.co>

* Change from error to warning high revalidate value

* Add find-pages-dir

* Add support for src directory

* Add test for pages dir preference

* Update comment

* initial commit for SPRv2

* Add initial SPR cache handling

* update SPR handling

* Implement SPR handling in render

* Update tests, handle caching with serverless next
start, add TODOs, and update manifest generating

* Handle no prerender-manifest from not being used

* Fix url.parse error

* Apply suggestions from code review
Co-Authored-By: NJoe Haddad <joe.haddad@zeit.co>

* Replace set with constants in next-page-config

* simplify sprStatus.used

* Add error if getStaticProps is used with getInitialProps

* Remove stale TODO

* Update revalidate values in SPR cache for non-seeded routes

* Apply suggestions from code review

* Remove concurrency type

* Rename variable for clarity

* Add copying prerender files during export

* Add comment for clarity

* Fix exporting

* Update comment

* Add additional note

* Rename variable

* Update to not re-export SPR pages from build

* Hard navigate when fetching data fails

* Remove default extension

* Add brackets

* Add checking output files to prerender tests

* Adjust export move logic

* Clarify behavior of export aggregation

* Update variable names for clarity

* Update tests

* Add comment

* s/an oxymoron/contradictory/

* rename

* Extract error case

* Add tests for exporting SPR pages and update
/_next/data endpoint to end with .json

* Relocate variable

* Adjust route building

* Rename to unstable

* Rename unstable_getStaticParams

* Fix linting

* Only add this when a data request

* Update prerender data tests

* s/isServerless/isLikeServerless/

* Don't rely on query for `next start` in serverless mode

* Rename var

* Update renderedDuringBuild check

* Add test for dynamic param with bracket

* Fix serverless next start handling

* remove todo

* Adjust comment

* Update calculateRevalidate

* Remove cache logic from render.tsx

* Remove extra imports

* Move SPR cache logic to next-server

* Remove old isDynamic prop

* Add calling App getInitialProps for SPR pages

* Update revalidate logic

* Add isStale to SprCacheValue

* Update headers for SPR

* add awaiting pendingRevalidation

* Dont return null for revalidation render

* Adjust logic

* Be sure to remove coalesced render

* Fix data for serverless

* Create a method coalescing utility

* Remove TODO

* Extract send payload helper

* Wrap in-line

* Move around some code

* Add tests for de-duping and revalidating

* Update prerender manifest test

* Global CSS Support

* Fix webpack configuration

* oneOf rule isn't necessary yet

* Adjust CSS chunk naming

* Begin testing CSS behavior

* Add another test TODO

* Replace null-loader with ignore-loader

* Turn on chunks for new CSS feature

* Fix multi test suite

* Test CSS import order

* Test style HMR

* Test CSS compilation

* Test compilation and prefixing together

* Verify CSS styling works for Development and Production

* Add missing TODO

* Remove unnecessary test

* Adjust TODO message

* Hide page until React hydrates

* Revert "Hide page until React hydrates"

This reverts commit 898d4e0ee547b003d5790e2b11476740d645b907.

* Hide FOUC during development

* Test CSS imports

* Update tests TODO

* Add fixture for url() test

* Test `file-loader` support in CSS files

* Use a simple variant of cssnano

* Self-import

* Undo bundling

* Implement suggestion