* Strip flow syntax before any other transform
Plugins run before presets so we can't use the flow preset

* Add informative comment

 - babel-preset-react-app@5.0.0
 - react-app-polyfill@0.1.1
 - react-dev-utils@6.0.1
 - react-error-overlay@5.0.1
 - react-scripts@2.0.1

* 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

Regenerator is already included by preset-env.

Fixes #4627

 - babel-plugin-named-asset-import@0.2.0
 - babel-preset-react-app@4.0.0
 - confusing-browser-globals@1.0.1
 - create-react-app@2.0.0
 - eslint-config-react-app@3.0.0
 - react-app-polyfill@0.1.0
 - react-dev-utils@6.0.0
 - react-error-overlay@5.0.0
 - react-scripts@2.0.0

* 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

* 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

https://github.com/facebook/create-react-app/pull/5046#issuecomment-423501823

* Correct babel dependency compile target

* Correctly compile runtime for dependencies

Closes #4932, Closes #4876

- [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 it...

Update babel-plugin-macros to 2.2.1.

* Enable loose mode for `class-properties`

* Update comment to point to discussion

Resolves #4263 

* Add explicit dep on plugin-proposal-object-rest-spread to babel-preset-react-app

* Bump babel-related deps to beta.42

* Pass useBuiltIns directly to react-preset

* feat: add opt-out for prestet-flow to work with @babel/preset-typescript

* docs: adding example in readme

* Remove PropTypes from production build (#209)

* Added react/forbid-foreign-prop-types rule to eslint config

* Removed react/forbid-foreign-prop-types rule from eslint config

* Try to fix CI

* Bump Jest elsewhere

* Bump Babel elsewhere

* Fix CI on Windows by writing .cmd file back

* Bump dependencies

* Use a more sensible way to compile error overlay

* Keep old chalk for global CLI

* Provide better defaults

* Let babel determine features to compile

* meh

* Remove setting of BABEL_ENV

* Revert "Remove setting of BABEL_ENV"

This reverts commit ee2db707.

* Set browsers to ie9

* Update dependencies in react-scripts

* Add first pass of working dependencies for babel-preset-react-app and react-scripts

* Bump more dependency versions

* Adjust more versions and edit fix options

* Restore functionality of old preset

* Disable Uglify in iframe webpack

* Apply prettier

* Re-enable cache in dev and clean deps

* Lock packages and move babel/core to dep in preset

* Bump babel-jest

* Re-enable uglify

* Nest forceAllTransforms correctly in webpack config

* Install babel-core bridge for jest

* Add jest-cli and babel-core bridge to make tests in react-error-overlay pass

* Re-enable transform-dynamic-import

* Add dynamic import syntax support back

* Use new babel in kitchensink

* Transform modules in test

* Revert "Transform modules in test"

This reverts commit 539e46a1.

* Attempt fix for ejected tests

* try this

* Add regenerator back

* Bump babel deps to beta.34

* Remove bad files

* Use default when requiring babel transform plugin

* Bump deps

* Try the fix?

* Oopsie

* Remove some weird things

* Run Babel on react-error-overlay tests

* Try fixing kitchensink

* Use new API for codeFrame

* Add missing (?) babelrc

* Maybe this helps?

* Maybe fix mocha

* I shouldn't have deleted this 

* add experimental babel-plugin-macros support

closes #2730

This will remain undocumented until the brave have tried it in the wild.

**Test Plan:**

There's currently no established way to test changes to
`babel-preset-react-app`. But I did create
[`unmaintained-react-scripts-babel-macros`](https://www.npmjs.com/package/unmaintained-react-scripts-babel-macros)
[a while back](https://github.com/facebookincubator/create-react-app/issues/2730#issuecomment-328153982)
and it worked well.

* Pin the version

 - babel-preset-react-app@3.1.1
 - create-react-app@1.5.0
 - eslint-config-react-app@2.1.0
 - react-dev-utils@5.0.0
 - react-error-overlay@4.0.0
 - react-scripts@1.1.0