# Fixes https://github.com/zeit/next.js/issues/5674
This adds config option
```js
// next.config.js
module.exports = {
crossOrigin: 'anonymous'
}
```
This config option is defined in the webpack Define Plugin at build.
`Head` and `NextScript` now use the config option, if it's not explicitly set on the element.
This value is now passed to Webpack so it can add it to scripts that it loads.
The value is now used in `PageLoader` (on the client) so it can add it to the scripts and links that it loads.
Using `<Head crossOrigin>` or `<NextScript crossOrigin>` is now deprecated.
* show warning if there is a title in _document.js Head
* dont loop through children in production
* only 1 loop through this.props.children 💪
* also raise warning in test env
* check for null childs
* Throw error if getInitialProps is defined as as instance method
Omitting the static keyword happens pretty often. Therefore we should trigger a warning in devmode.
Closes: #4782
* Document getInitialProps error
* Add unit tests for loadGetInitialProps
* Expose pages/_app.js
* Add tests for _app and _document
* Uncomment deprecation warnings
* Add documentation for _app, improve documentation of _document
* Update docs / test for _document
* Add _document to client compiler in development
* Add missing app.js to comment
* Only warn once
* Add url-deprecated error page
* Combine tests
* Yse same message for all methods of ‘props.url’
* Update docs around _app
* Update documentation
* Quotes
* Update table of contents
* Remove special error script handling.
As a result of that, we can't detect 500 errors and buildIdMismatch via client side.
* Fix failing test cases.
* Refactor the code base.
* Remove Router.onAppUpdated
This reverts `fb7c862` per @timneutkens
- Removes the errors/*.md associated
- Puts back `poweredByHeader` for `next.config.js`
- Reincorporates test:
X-Powered-By header
✓ should set it by default (3ms)
✓ should not set it when poweredByHeader==false (5ms)
Also tested with `yarn link` and verified.
* Speed up next build
* Document webpack config
* Speed up next build
* Remove comment
* Add comment
* Clean up rules
* Add comments
* Run in parallel
* Push plugins seperately
* Create a new chunk for react
* Don’t uglify react since it’s already uglified. Move react to commons in development
* Use the minified version directly
* Re-add globpattern
* Move loaders into a separate variable
* Add comment linking to Dan’s explanation
* Remove dot
* Add universal webpack
* Initial dev support
* Fix linting
* Add changes from Arunoda's work
* Made next dev works.
But super slow and no HMR support.
* Fix client side hot reload
* Server side hmr
* Only in dev
* Add on-demand-entries client + hot-middleware
* Add .babelrc support
* Speed up on demand entries by running in parallel
* Serve static generated files
* Add missing config in dev
* Add sass support
* Add support for .map
* Add cssloader config and fix .jsx support
* Rename
* use same defaults as css-loader. Fix linting
* Add NoEmitErrorsPlugin
* Add clientBootstrap
* Use webpackhotmiddleware on the multi compiler
* alpha.3
* Use babel 16.2.x
* Fix reloading after error
* Remove comment
* Release 5.0.0-univeral-alpha.1
* Remove check for React 16
* Release 5.0.0-universal-alpha.2
* React hot loader v4
* Use our static file rendering machanism to serve pages.
This should work well since the file path for a page is predictable.
* Release 5.0.0-universal-alpha.3
* Remove optional loaders
* Release 5.0.0-universal-alpha.4
* Remove clientBootstrap
* Remove renderScript
* Make sure pages bundles are served correctly
* Remove unused import
* Revert to using the same code as canary
* Fix hot loader
* Release 5.0.0-universal-alpha.5
* Check if externals dir exist before applying config
* Add typescript support
* Add support for transpiling certain packages in node_modules
Thanks to @giuseppeg’s work in https://github.com/zeit/next.js/pull/3319
* Add BABEL_DISABLE_CACHE support
* Make sourcemaps in production opt-in
* Revert "Add support for transpiling certain packages in node_modules"
This reverts commit d4b1d9babfb4b9ed4f4b12d56d52dee233e862da.
In favor of a better api around this.
* Support typescript through next.config.js
* Remove comments
* Bring back commons.js calculation
* Remove unused dependencies
* Move base.config.js to webpack.js
* Make sure to only invalidate webpackDevMiddleware one after other.
* Allow babel-loder caching by default.
* Add comment about preact support
* Bring back buildir replace
* Remove obsolete plugin
* Remove build replace, speed up build
* Resolve page entries like pages/day/index.js to pages/day.js
* Add componentDidCatch back
* Compile to bundles
* Use config.distDir everywhere
* Make sure the file is an array
* Remove console.log
* Apply optimization to uglifyjs
* Add comment pointing to source
* Create entries the same way in dev and production
* Remove unused and broken pagesGlobPattern
* day/index.js is automatically turned into day.js at build time
* Remove poweredByHeader option
* Load pages with the correct path.
* Release 5.0.0-universal-alpha.6
* Make sure react-dom/server can be overwritten by module-alias
* Only add react-hot-loader babel plugin in dev
* Release 5.0.0-universal-alpha.7
* Revert tests
* Release 5.0.0-universal-alpha.10
* Make sure next/head is working properly.
* Add wepack alias for 'next' back.
* Make sure overriding className in next/head works
* Alias react too
* Add missing r
* Fragment fallback has to wrap the children
* Use min.js
* Remove css.js
* Remove wallaby.js
* Release 5.0.0-universal-alpha.11
* Resolve relative to workdir instead of next
* Make sure we touch the right file
* Resolve next modules
* Remove dotjsx removal plugins since we use webpack on the server
* Revert "Resolve relative to workdir instead of next"
This reverts commit a13f3e4ab565df9e2c9a3dfc8eb4009c0c2e02ed.
* Externalize any locally loaded module lives outside of app dir.
* Remove server aliases
* Check node_modules reliably
* Add symlink to next for tests
* Make sure dynamic imports work locally.
This is why we need it: b545b519b2/lib/MainTemplate.js (L68)
We need to have the finally clause in the above in __webpack_require__.
webpack output option strictModuleExceptionHandling does that.
* dynmaic -> dynamic
* Remove webpack-node-externals
* Make sure dynamic imports support SSR.
* Remove css support in favor of next-css
* Make sure we load path from `/` since it’s included in the path matching
* Catch when ensurepage couldn’t be fulfilled for `.js.map`
* Register require cache flusher for both client and server
* Add comment explaining this is to facilitate hot reloading
* Only load module when needed
* Remove unused modules
* Release 5.0.0-universal-alpha.12
* Only log the `found babel` message once
* Make sure ondemand entries working correctly.
Now we are just using a single instance of OnDemandEntryHandler.
* Better sourcemaps
* Release 5.0.0-universal-alpha.13
* Lock uglify version to 1.1.6
* Release 5.0.0-universal-alpha.14
* Fix a typo.
* Introduce multi-zones support for mircofrontends
* Add section on css
