* Tweak environment handling

* Add documentation for getCacheIdentifier

* Upgrade html webpack plugin

* Fix build

- [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

* Update CSS Modules localIndetName

* Add missing file to package

* Correct regex

* plz plz plz

* allow appSrc accepting an array

* fixture of finding all appSrcs logic

* update docs on ModuleScopePlugin accepts an array for appSrc

* minor typo fix in docs: change directory to directories.

* Fix docs for `printFileSizesAfterBuild`

* Add optionals parameters for `printFileSizesAfterBuild`

* Allow importing package.json

* Remove package.json import from App.js template

* fix importing package.json

* Rename variable to reflect path is relative to root

* Check for both package & package.json in ModuleScopePlugin

* Use regex to check relative path to package.json

* Strictly enforce package.json extension on scope plugin

* Add allowedPaths to ModuleScopePlugin ctor and use it to allow app package.json

* Remove package.json import from App.js template

* Add package.json to react-scripts/template, show package version and name in the template

* Remove import package.json from template

* Remove template/package.json and its references in code

* Update ModuleScopePlugin.js

* Update README.md

* format UglifyJs error

* move formatBuildError to react-dev-utils

* fix readme

* use regex for plucking the path from stack

* make path human readable and fallback to show error if regex not matched

* rename to printBuildError and add link to the docs

* fix link indentation

* improve readibility + shorten link

* Remove note about webpackHotDevClient being webpack 1.0 only

It must work in webpack 2 since create-react-app is still using it and is using webpack 2 now.

It would be great if you could add some kind of note about how it differs from the default webpack hot reloaders.

* Update README.md

* Update README.md

* Provide a no-op SW that will be served by the dev environment.

* Hide no-op service worker from user

* Show warnings for builds

* Move WebpackDevServer helpers into react-dev-utils

* Correct readme

* Add tests

* Update README.md

* Add module scope plugin

* Oops

* Add comments

* Check windows seps too

* More descriptive error

* Document it

* Add custom eslint formatter

* Add formatter docs

* Update formatter docs

* Slightly tweak it

* Update README.md

* Temp rename

* Rename to change the case

* extract generic build functions to react-dev-utils

* tweak package json files and move removeFileNameHash

* revert removeFileNameHash

* use paths.appBuild in printFileSizes

* use paths.appBuild in removeFileNameHash

* change curried functions to regular functions

* add fs-extra to react-dev-utils deps

* move getDifferenceLabel inside printFileSizes

* inline copyPublicFolder

* combine printFileSizes and removeFileNameHash to fileSizeReporter

* fix typo

* Tweak APIs and fix issues

* Fix heading

* Remove missing file

* Newline

* Newline

* Trailing space

* Update FileSizeReporter.js

* Update build.js

* Add note for using CHOKIDAR_USEPOLLING in virtual machines to enable HMR

* Use br in react-scripts template README md

* Use br in md for new line breaks

* Update troubleshooting HMR to allow for VMs running Windows

* Fix up the instructions

Array.forEach is passed the following parameters:

currentValue
    The current element being processed in the array.
index
    The index of the current element being processed in the array.
array
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

console.log takes multiple arguments. We only want to print the first one, the actually message.

* add logging of existing port process on start

* Move port process wording in start command on to next line

* Color the named processes as cyan in terminal output

* Add handling for multiple processes on a part

- With the currently process filtering, if multiple processes are returned as running on port 3000, this command would fail. This splits apart the process IDing and the process naming, to support multiple processes.
- One curious thing about the bash command to get processes, is that it'll include browsers with a window open on localhost:3000. May want to reconsider that.

* Add process directory to existing port warning

- also moved terminal coloring up, when getting the process, to be able to distinguish the process command from the directory

* Change output color to all cyan, except "in"

* Rename getProcessNameOnPort -> getProcessForPort

- better reflects its broadened scope (both command and directory)

* Add checking if process is a CRA instance, to customize port running message

- moved from using package.json to a regex, for reliability

* Move getProcessForPort to react-dev-utils

- also allowed for breakdown of commands into helper methods

* Add documentation for getProcessForPort

* Add getProcessForPort to list of dev-scripts files

* Use app's package name when CRA app is running on another port

* Filter port process by those listening

- Removed the handling of multiple process IDs since you can filtering by listening process (and not have the browser in the list of processes)
- Trimmed the terminal outputs for better matching (process id) and better terminal output (directory of process)

* Update README on port helpers, to specify only one port returned

* Add ignore of stderr when executing process commands

- Make sure any potential errors don't leak to the user

* Add syntax error overlay in development

* Support HMR being disabled

* Tweak CSS

* Extract some utilities into a separate package

* Add utils dir to `files` in package.json

* Do not create an empty `utils` dir on eject