* Always type check TypeScript when being used

* Use alternate version

* Add `.mjs` support back to webpack, because webpack was not the problem

* Continue toggling `.mjs` to `javascript/auto` mode

* Be more inline with the specification

* Bump old Node to 6

* Adds the PnP plugin for Webpack to find dependencies when working under PnP

* Adds configuration for jest

* Adds an e2e test for when using PnP

* Avoids cra from crashing at the engine check

* Avoids cra from crashing when initializing react-scripts

* Makes the ownPath portable

* Fixes linting

* Bumps to pnp-webpack-plugin@1.1.0, removes symlinks: false

* Adds a --use-pnp option

* Pin version

* Only install react-scripts in CI mode

* Link locally

* Re-enable all output tests

*  Polish webpack output

* Test sass support message

* Add more tests, but disabled

* Format missing default export error

* Format aliased import

* Why was node-sass required? Odd

* Format webpack rejection error

* Re-enable unknown package test

* Format file not found error and catch module scope plugin error

* Re-disable case sensitive paths

* Intercept and format case sensitive path errors

* Test out of scope message formatting

* Run behavior on macOS

* Run behavior on Node 8 and 10, only Node 8 for macOS

* Add some debugging

* Update matcher

* Only check stderr

* Remove old snapshot

* More debug

* Remove debug

* Add new debug

* Disable test on linux

* Add comment for future

* Remove thread-loader
After the cache is warm, it is possible for thread-loader to hurt speed

* Disable babel output formatting

* Forwards args through thread-loader

* Comments & dev

* Switch back to babel-loader

* Preserve existing caller options. Use Object.assign instead of object spread.

* Updated filename in package.json

* Update comment about cache identifier

* Update macro check to use a regex

* Move macro check regex out of function

* Remove runtime alias hack

* Pass absolute path to preset

* Change comment

* Give a relative path to absolute runtime

* Clean up config

* Tweak again

* Make absolute runtime the default

* Remove runtime package from error overlay

* Turn on helpers and test importing something with async/await works

* Compiling babel runtime breaks itself

* Add helpers option to babel plugin with defaults

* Make helpers off by default and on in our configuration

* Hit eject and e2e

* meh

* copy'n'paste

* change again

* Turn off helpers by default in /prod, /dev, /test

* oops

* Spread undefined

* Use object assign not object spread

* Put preset in template since it's needed

* Fix e2e tests

* Drop ie 11 support and move polyfills to a new package

* More useful directions for what entry point to use
https://github.com/facebook/create-react-app/pull/5090#discussion_r220313783

* Clear up what file this polyfill goes in
https://github.com/facebook/create-react-app/pull/5090#discussion_r220313980

* Polyfill `window`, not `global`

* Remove proxy polyfill file

* Switch to stage 3 css

* Tweak default browsers, too

* add postcss-preset-env, remove autoprefixer

* limit to stage 4

* Add new overrides option

* Add file to package.json

* Create our own loader

* Remove overrides

* We have to use a real babel option

* Add comments

This is the best behavior so people have seamless upgrades to new React majors.

This is probably a terrible default warning from the ESLint plugin, and we need to wait for https://github.com/yannickcr/eslint-plugin-react/issues/1955 before changing this hardcoded behavior.

Closes #5034

* Upgrade html webpack plugin

* Fix build

* Disable webpack chunk rollup

* Bump timeout

* Revert "Bump timeout"

This reverts commit 84632115d178b48e08eb75dc5e9a921ece6aa759.

* Revert Lerna dependency, there's too many bugs in v3

* Remove `mjs` support

This reverts commit b43ad04b.

The `formatter` option is incompatible with with `thread-loader`.
The `formatter` option previously accepted a function which was lost during JSON serialization.

- [x] Utilize webpack 4 development and production modes
- [x] Upgrade webpack dev server
- [x] Webpack 4 compatible release of thread-loader
- [x] Webpack 4 compatible release of HtmlWebpackPlugin
- [x] Webpack 4 compatible release of SwPrecacheWebpackPlugin
- [x] Webpack 4 compatible release of WebpackManifestPlugin
- [x] Update README
- [x] Update WebpackDevServerUtils
- [x] Update InterpolateHtmlPlugin
- [x] Update ModuleScopePlugin
- [x] Update WatchMissingNodeModulesPlugin
- [x] Move UglifyJS options to webpack 4 optimize
- [x] Move InterpolateHtmlPlugin to make it tapable on HtmlWebpackPlugin
- [x] vendor splitting via splitChunks.splitChunks (https://twitter.com/wSokra/status/969633336732905474)
- [x] long term caching via splitChunks.runtimeChunk (https://twitter.com/wSokra/status/969679223278505985)
- [x] Make sure process.env.NODE_ENV is proxied correctly to `react-error-overlay`
- [x] Implicit webpack.NamedModulesPlugin in dev config as its default in webpack 4
- [x] Disable webpack performance hints as we have our own filesize reporter
- [x] Replace ExtractTextPlugin with MiniCssExtractPlugin
- [x] Switch to css whole file minification via OptimizeCSSAssetsPlugin rather than per module css minification to gain performance

* Installs and adds sass loader task in webpack for dev environment.

* Uses Timer's branch of sass-loader without node-sass dependency.

* Adds method for handling SASS modules.

* Fixes extension of excluded files when looking for scss modules.

* Adds support for both .scss and .sass extensions.

* Uses ExtractTextPlugin with sass-loader to bundle styles for the production build.

* Bundles SASS modules for the production build.

* Uses the latest version of sass-loader.

* Adds function to create different rules for style loaders in dev environment.

* Abstracts style loaders to a common function to avoid repetition.

* Simplifies the common function that creates style loaders.

* Creates assets for testing SASS/SCSS support.

* Creates mock components and unit tests for SASS and SCSS with and without modules.

* Creates integration tests for SASS/SCSS support.

* Adds node-sass as a template dependency so sass-loader can be tested.

* Includes sass tests when test component is mounted.

* Fixes asserted module name for sass and scss modules tests.

* Removes tests against css imports in SCSS and SASS files.

* Updates sass-loader to v7.

* Uses getCSSModuleLocalIdent from react-dev-utils.

* Fixes tests to match the use of getCSSModuleLocalIdent.

* Improves readability of getStyleLoader function.

* Uses postcss after sass.

* Refactors dev config to simplify common function for style loaders.

* Refactors prod config to simplify common function for style loaders.

* Use importLoaders config according to css-loader docs.

* Update CSS Modules localIndetName

* Add missing file to package

* Correct regex

* plz plz plz

* Add graphql loader to webpack config

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Update README.md

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Update react-scripts README.md

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Add graphql jest transform

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Add integration tests, pin versions in package.json

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Tests expect regexp matchers

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Use strict equal test instead

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Escaping is hard

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Add comment for signifying a different file

* Update docs

* Fix jest config

* Remove node_modules exclusion

* Update README.md

* Inline graphql jest transform

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Update copyright header

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Use .graphql extension only

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>