Merge remote-tracking branch 'origin/master' into css-modules

.babelrc

@@ -28,6 +28,26 @@
         "@babel/preset-env",
         "babel-preset-vue"
       ]
+    },
+    {
+      "test": [
+        "./lib/core/src/server",
+        "./lib/node-logger",
+        "./lib/codemod",
+        "./addons/storyshots",
+        "./addons/storysource/src/loader",
+        "./app/**/src/server/**"
+      ],
+      "presets": [
+        [
+          "@babel/preset-env",
+          {
+            "targets": {
+              "node": "8.11"
+            }
+          }
+        ]
+      ]
     }
   ]
 }

MIGRATION.md

@@ -173,7 +173,7 @@ If you're using `start-storybook` on CI, you may need to opt out of this using t
 We've deprecated the `getstorybook` CLI in 4.0. The new way to install storybook is `sb init`. We recommend using `npx` for convenience and to make sure you're always using the latest version of the CLI:
 
 ```
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 ## From version 3.3.x to 3.4.x

README.md

@@ -55,7 +55,7 @@ First install storybook:
 
 ```sh
 cd my-react-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 If you'd rather set up your project manually, take a look at our [Slow Start Guide](https://storybook.js.org/basics/slow-start-guide/).
@@ -66,7 +66,7 @@ Once it's installed, you can `npm run storybook` and it will run the development
 
 ```sh
 cd my-storybook-v2-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 It runs a codemod to update all package names. Read all migration details in our [Migration Guide](MIGRATION.md)

app/angular/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-angular-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/angular/package.json

@@ -40,7 +40,7 @@
     "sass-loader": "^7.1.0",
     "ts-loader": "^5.2.2",
     "tsconfig-paths-webpack-plugin": "^3.2.0",
-    "webpack": "^4.20.2",
+    "webpack": "^4.21.0",
     "zone.js": "^0.8.26"
   },
   "peerDependencies": {

app/angular/src/server/angular-cli_config.js

@@ -2,7 +2,12 @@ import path from 'path';
 import fs from 'fs';
 import { logger } from '@storybook/node-logger';
 import { TsconfigPathsPlugin } from 'tsconfig-paths-webpack-plugin';
-import { isBuildAngularInstalled, normalizeAssetPatterns } from './angular-cli_utils';
+import {
+  isBuildAngularInstalled,
+  normalizeAssetPatterns,
+  filterOutStylingRules,
+  getAngularCliParts,
+} from './angular-cli_utils';
 
 function getTsConfigOptions(tsConfigPath) {
   const basicOptions = {
@@ -27,20 +32,6 @@ function getTsConfigOptions(tsConfigPath) {
   return basicOptions;
 }
 
-function getAngularCliParts(cliWebpackConfigOptions) {
-  // eslint-disable-next-line global-require, import/no-extraneous-dependencies
-  const ngCliConfigFactory = require('@angular-devkit/build-angular/src/angular-cli-files/models/webpack-configs');
-
-  try {
-    return {
-      cliCommonConfig: ngCliConfigFactory.getCommonConfig(cliWebpackConfigOptions),
-      cliStyleConfig: ngCliConfigFactory.getStylesConfig(cliWebpackConfigOptions),
-    };
-  } catch (e) {
-    return null;
-  }
-}
-
 export function getAngularCliWebpackConfigOptions(dirToSearch) {
   const fname = path.join(dirToSearch, 'angular.json');
 
@@ -107,12 +98,9 @@ export function applyAngularCliWebpackConfig(baseConfig, cliWebpackConfigOptions
 
   const { cliCommonConfig, cliStyleConfig } = cliParts;
 
-  // Don't use storybooks .css/.scss rules because we have to use rules created by @angular-devkit/build-angular
+  // Don't use storybooks styling rules because we have to use rules created by @angular-devkit/build-angular
   // because @angular-devkit/build-angular created rules have include/exclude for global style files.
-  const rulesExcludingStyles = baseConfig.module.rules.filter(
-    rule =>
-      !rule.test || (rule.test.toString() !== '/\\.css$/' && rule.test.toString() !== '/\\.scss$/')
-  );
+  const rulesExcludingStyles = filterOutStylingRules(baseConfig);
 
   // cliStyleConfig.entry adds global style files to the webpack context
   const entry = {

app/angular/src/server/angular-cli_utils.js

@@ -23,6 +23,24 @@ function getAssetsParts(resolvedAssetPath, assetPath) {
   };
 }
 
+function isStylingRule(rule) {
+  const { test } = rule;
+
+  if (!test) {
+    return false;
+  }
+
+  if (!(test instanceof RegExp)) {
+    return false;
+  }
+
+  return test.test('.css') || test.test('.scss') || test.test('.sass');
+}
+
+export function filterOutStylingRules(config) {
+  return config.module.rules.filter(rule => !isStylingRule(rule));
+}
+
 export function isBuildAngularInstalled() {
   try {
     require.resolve('@angular-devkit/build-angular');
@@ -32,6 +50,20 @@ export function isBuildAngularInstalled() {
   }
 }
 
+export function getAngularCliParts(cliWebpackConfigOptions) {
+  // eslint-disable-next-line global-require, import/no-extraneous-dependencies
+  const ngCliConfigFactory = require('@angular-devkit/build-angular/src/angular-cli-files/models/webpack-configs');
+
+  try {
+    return {
+      cliCommonConfig: ngCliConfigFactory.getCommonConfig(cliWebpackConfigOptions),
+      cliStyleConfig: ngCliConfigFactory.getStylesConfig(cliWebpackConfigOptions),
+    };
+  } catch (e) {
+    return null;
+  }
+}
+
 export function normalizeAssetPatterns(assetPatterns, dirToSearch, sourceRoot) {
   if (!assetPatterns || !assetPatterns.length) {
     return [];

app/angular/src/server/framework-preset-angular.js

@@ -31,7 +31,7 @@ export function webpack(config, { configDir }) {
           exclude: /\.async\.html$/,
         },
         {
-          test: /\.scss$/,
+          test: /\.s(c|a)ss$/,
           use: [require.resolve('raw-loader'), require.resolve('sass-loader')],
         },
       ],

app/ember/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-ember-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/html/README.md

@@ -14,7 +14,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-app
-npx -p @storybook/cli@alpha sb init -t html
+npx -p @storybook/cli@rc sb init -t html
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/marko/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-marko-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/mithril/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-mithril-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/polymer/README.md

@@ -14,7 +14,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-polymer-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/polymer/package.json

@@ -35,7 +35,7 @@
     "global": "^4.3.2",
     "react": "^16.5.2",
     "react-dom": "^16.5.2",
-    "webpack": "^4.20.2"
+    "webpack": "^4.21.0"
   },
   "devDependencies": {
     "lit-html": "^0.12.0",

app/react-native/package.json

@@ -63,7 +63,7 @@
     "shelljs": "^0.8.2",
     "url-parse": "^1.4.3",
     "uuid": "^3.3.2",
-    "webpack": "^4.20.2",
+    "webpack": "^4.21.0",
     "webpack-dev-middleware": "^3.4.0",
     "webpack-hot-middleware": "^2.24.3",
     "ws": "^6.1.0"

app/react-native/readme.md

@@ -12,7 +12,7 @@ The `storybook` CLI tool can be used to add Storybook to your React Native app.
 
 ```shell
 cd my-rn-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 The next thing you need to do is make Storybook UI visible in your app.

app/react/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-react-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/riot/README.md

@@ -14,7 +14,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-riot-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/svelte/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-svelte-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

app/vue/README.md

@@ -12,7 +12,7 @@ So you can develop UI components in isolation without worrying about app specifi
 
 ```sh
 cd my-vue-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)

docs/src/pages/basics/faq/index.md

@@ -1,8 +1,7 @@
-* * *
-
+---
 id: 'faq'
-
-## title: 'Frequently Asked Questions'
+title: 'Frequently Asked Questions'
+---
 
 Here are some answers to frequently asked questions. If you have a question, you can ask it by opening an issue on the [Storybook Repository](https://github.com/storybooks/storybook/).
 

docs/src/pages/basics/quick-start-guide/index.md

@@ -10,13 +10,13 @@ Get started using the automated command line tool. This command adds a set of bo
 
 ```sh
 cd my-project-directory
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 The tool inspects your `package.json` to determine which view layer you're using. If you want to develop HTML snippets in storybook, we can't determine that automatically. So to install storybook for HTML, use the `--type` flag to force that the HTML project type:
 
 ```
-npx -p @storybook/cli@alpha sb init --type html
+npx -p @storybook/cli@rc sb init --type html
 ```
 
 To setup a project manually, take a look at the [Slow Start Guide](/basics/slow-start-guide/).

examples/ember-cli/package.json

@@ -39,7 +39,7 @@
     "ember-resolver": "^5.0.1",
     "ember-source": "~3.5.0",
     "loader.js": "^4.2.3",
-    "webpack": "^4.17.1",
+    "webpack": "^4.21.0",
     "webpack-cli": "^3.1.2"
   },
   "engines": {

examples/marko-cli/package.json

@@ -29,6 +29,6 @@
     "@storybook/addons": "4.0.0-rc.1",
     "@storybook/marko": "4.0.0-rc.1",
     "prettier": "^1.14.3",
-    "webpack": "^4.20.2"
+    "webpack": "^4.21.0"
   }
 }

examples/mithril-kitchen-sink/package.json

@@ -22,6 +22,6 @@
     "@storybook/addon-viewport": "4.0.0-rc.1",
     "@storybook/addons": "4.0.0-rc.1",
     "@storybook/mithril": "4.0.0-rc.1",
-    "webpack": "^4.20.2"
+    "webpack": "^4.21.0"
   }
 }

examples/official-storybook/package.json

@@ -9,7 +9,7 @@
     "generate-addon-jest-testresults": "jest --config=tests/addon-jest.config.json --json --outputFile=stories/addon-jest.testresults.json",
     "graphql": "node ./graphql-server/index.js",
     "image-snapshots": "yarn run build-storybook && yarn run do-image-snapshots",
-    "storybook": "STORYBOOK_DISPLAY_WARNING=true DISPLAY_WARNING=true start-storybook -p 9011 -c ./ -s built-storybooks"
+    "storybook": "cross-env STORYBOOK_DISPLAY_WARNING=true DISPLAY_WARNING=true start-storybook -p 9011 -c ./ -s built-storybooks"
   },
   "devDependencies": {
     "@emotion/core": "^0.13.1",
@@ -37,6 +37,7 @@
     "@storybook/node-logger": "4.0.0-rc.1",
     "@storybook/react": "4.0.0-rc.1",
     "cors": "^2.8.4",
+    "cross-env": "^5.2.0",
     "enzyme-to-json": "^3.3.4",
     "eventemitter3": "^3.1.0",
     "express": "^4.16.3",
@@ -50,6 +51,6 @@
     "react-chromatic": "^0.8.4",
     "react-dom": "^16.5.2",
     "uuid": "^3.3.2",
-    "webpack": "^4.20.2"
+    "webpack": "^4.21.0"
   }
 }

examples/official-storybook/webpack.config.js

@@ -1,7 +1,7 @@
 const path = require('path');
 const { DefinePlugin, ContextReplacementPlugin } = require('webpack');
 
-module.exports = (baseConfig, env, defaultConfig) => ({
+module.exports = async (baseConfig, env, defaultConfig) => ({
   ...defaultConfig,
   module: {
     ...defaultConfig.module,

examples/polymer-cli/package.json

@@ -22,7 +22,7 @@
     "global": "^4.3.2",
     "lit-html": "^0.12.0",
     "polymer-webpack-loader": "^2.0.3",
-    "webpack": "^4.20.2"
+    "webpack": "^4.21.0"
   },
   "devDependencies": {
     "copy-webpack-plugin": "^4.5.3",

examples/riot-kitchen-sink/package.json

@@ -33,7 +33,7 @@
     "raw-loader": "^0.5.1",
     "riot-tag-loader": "^2.1.0",
     "svg-url-loader": "^2.3.2",
-    "webpack": "^4.20.2",
+    "webpack": "^4.21.0",
     "webpack-dev-server": "^3.1.9"
   }
 }

examples/vue-kitchen-sink/package.json

@@ -32,7 +32,7 @@
     "file-loader": "^2.0.0",
     "svg-url-loader": "^2.3.2",
     "vue-loader": "^15.4.2",
-    "webpack": "^4.20.2",
+    "webpack": "^4.21.0",
     "webpack-dev-server": "^3.1.9"
   }
 }

lib/cli/README.md

@@ -10,7 +10,7 @@ Just go to your project and run:
 
 ```sh
 cd my-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 That's all you've to do.
@@ -24,7 +24,7 @@ The CLI supports yarn. If you have installed yarn in your system, it'll detect i
 If you don't want to use `yarn` always you can use the `--use-npm` option like this:
 
 ```sh
-npx -p @storybook/cli@alpha sb init --use-npm
+npx -p @storybook/cli@rc sb init --use-npm
 ```
 
 ---
@@ -34,7 +34,7 @@ npx -p @storybook/cli@alpha sb init --use-npm
 It also supports flow files. By default, [jscodeshift](https://github.com/facebook/jscodeshift), the tool used to transform the source files, uses babel to read the files. To be able to transform any flow annotated file, you need to use the flow parser.
 
 ```sh
-npx -p @storybook/cli@alpha sb init --parser flow
+npx -p @storybook/cli@rc sb init --parser flow
 ```
 
 For more information visit: [storybook.js.org](https://storybook.js.org)
@@ -46,7 +46,7 @@ For more information visit: [storybook.js.org](https://storybook.js.org)
 If the CLI cannot detect your project type, it will ask you. You can also force it to use a particular project type:
 
 ```sh
-npx -p @storybook/cli@alpha sb init --type <type>
+npx -p @storybook/cli@rc sb init --type <type>
 ```
 
 Where type is one of the project types defined in [project_types.js](https://github.com/storybooks/storybook/blob/master/lib/cli/lib/project_types.js)

lib/cli/test/fixtures/react_scripts/README.md

@@ -1509,7 +1509,7 @@ Then, run the following command inside your app’s directory:
 
 ```sh
 cd my-react-app
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 After that, follow the instructions on the screen.

lib/cli/test/fixtures/update_package_organisations/README.md

@@ -1178,7 +1178,7 @@ You can also deploy your Storybook as a static app. This way, everyone in your t
 Then, run the following command inside your app’s directory:
 
 ```sh
-npx -p @storybook/cli@alpha sb init
+npx -p @storybook/cli@rc sb init
 ```
 
 After that, follow the instructions on the screen.

lib/core/package.json

@@ -78,7 +78,7 @@
     "style-loader": "^0.23.1",
     "svg-url-loader": "^2.3.2",
     "url-loader": "^1.1.2",
-    "webpack": "^4.20.2",
+    "webpack": "^4.21.0",
     "webpack-dev-middleware": "^3.4.0",
     "webpack-hot-middleware": "^2.24.3"
   },

lib/core/src/server/build-dev.js

@@ -134,7 +134,9 @@ export async function buildDevStandalone(options) {
 
     applyStatic(app, options);
 
-    app.use(storybook(options));
+    const storybookMiddleware = await storybook(options);
+
+    app.use(storybookMiddleware);
 
     const serverListening = listenToServer(server, listenAddr);
 

lib/core/src/server/build-static.js

@@ -8,7 +8,7 @@ import loadConfig from './config';
 
 const defaultFavIcon = require.resolve('./public/favicon.ico');
 
-export function buildStaticStandalone(options) {
+export async function buildStaticStandalone(options) {
   const { outputDir, staticDir, watch } = options;
 
   // create output directory if not exists
@@ -20,7 +20,7 @@ export function buildStaticStandalone(options) {
   // Build the webpack configuration using the `baseConfig`
   // custom `.babelrc` file and `webpack.config.js` files
   // NOTE changes to env should be done before calling `getBaseConfig`
-  const config = loadConfig({
+  const config = await loadConfig({
     configType: 'PRODUCTION',
     corePresets: [require.resolve('./core-preset-prod.js')],
     ...options,
@@ -63,10 +63,10 @@ export function buildStaticStandalone(options) {
   }
 }
 
-export function buildStatic({ packageJson, ...loadOptions }) {
+export async function buildStatic({ packageJson, ...loadOptions }) {
   const cliOptions = getProdCli(packageJson);
 
-  buildStaticStandalone({
+  await buildStaticStandalone({
     ...cliOptions,
     ...loadOptions,
     configDir: cliOptions.configDir || './.storybook',

lib/core/src/server/config.js

@@ -5,11 +5,11 @@ import serverRequire from './serverRequire';
 
 function wrapCorePresets(presets) {
   return {
-    babel: (config, args) => presets.apply('babel', config, args),
-    webpack: (config, args) => presets.apply('webpack', config, args),
-    webpackFinal: (config, args) => presets.apply('webpackFinal', config, args),
-    preview: (config, args) => presets.apply('preview', config, args),
-    manager: (config, args) => presets.apply('manager', config, args),
+    babel: async (config, args) => presets.apply('babel', config, args),
+    webpack: async (config, args) => presets.apply('webpack', config, args),
+    webpackFinal: async (config, args) => presets.apply('webpackFinal', config, args),
+    preview: async (config, args) => presets.apply('preview', config, args),
+    manager: async (config, args) => presets.apply('manager', config, args),
   };
 }
 
@@ -27,20 +27,20 @@ function customPreset({ configDir }) {
   return [];
 }
 
-function getWebpackConfig(options, presets) {
-  const babelOptions = presets.babel({}, options);
+async function getWebpackConfig(options, presets) {
+  const babelOptions = await presets.babel({}, options);
 
   const entries = {
-    iframe: presets.preview([], options),
-    manager: presets.manager([], options),
+    iframe: await presets.preview([], options),
+    manager: await presets.manager([], options),
   };
 
-  const webpackConfig = presets.webpack({}, { ...options, babelOptions, entries });
+  const webpackConfig = await presets.webpack({}, { ...options, babelOptions, entries });
 
   return presets.webpackFinal(webpackConfig, options);
 }
 
-export default options => {
+export default async options => {
   const { corePresets = [], frameworkPresets = [], ...restOptions } = options;
 
   const presetsConfig = [

lib/core/src/server/config/entries.js

@@ -1,8 +1,8 @@
-export function createPreviewEntry(options) {
+export async function createPreviewEntry(options) {
   const { configDir, presets } = options;
   const preview = [require.resolve('./polyfills'), require.resolve('./globals')];
 
-  const configs = presets.apply('config', [], options);
+  const configs = await presets.apply('config', [], options);
 
   if (!configs || !configs.length) {
     throw new Error(`=> Create a storybook config file in "${configDir}/config.{ext}".`);
@@ -13,11 +13,11 @@ export function createPreviewEntry(options) {
   return preview;
 }
 
-export function createManagerEntry(options) {
+export async function createManagerEntry(options) {
   const { presets } = options;
   const manager = [require.resolve('./polyfills')];
 
-  const addons = presets.apply('addons', [], options);
+  const addons = await presets.apply('addons', [], options);
 
   if (addons && addons.length) {
     manager.push(...addons);

lib/core/src/server/config/webpack.config.dev.js

@@ -71,7 +71,7 @@ export default ({ configDir, quiet, babelOptions, entries }) => {
     module: {
       rules: [
         {
-          test: /\.jsx?$/,
+          test: /\.(mjs|jsx?)$/,
           use: [
             {
               loader: 'babel-loader',
@@ -94,7 +94,7 @@ export default ({ configDir, quiet, babelOptions, entries }) => {
     resolve: {
       // Since we ship with json-loader always, it's better to move extensions to here
       // from the default config.
-      extensions: ['.js', '.jsx', '.json'],
+      extensions: ['.js', '.jsx', '.json', '.mjs'],
       // Add support to NODE_PATH. With this we could avoid relative path imports.
       // Based on this CRA feature: https://github.com/facebookincubator/create-react-app/issues/253
       modules: ['node_modules'].concat(nodePaths),

lib/core/src/server/config/webpack.config.prod.js

@@ -57,7 +57,7 @@ export default ({ configDir, babelOptions, entries }) => {
     module: {
       rules: [
         {
-          test: /\.jsx?$/,
+          test: /\.(mjs|jsx?)$/,
           use: [
             {
               loader: 'babel-loader',
@@ -80,7 +80,7 @@ export default ({ configDir, babelOptions, entries }) => {
     resolve: {
       // Since we ship with json-loader always, it's better to move extensions to here
       // from the default config.
-      extensions: ['.js', '.jsx', '.json'],
+      extensions: ['.js', '.jsx', '.json', '.mjs'],
       // Add support to NODE_PATH. With this we could avoid relative path imports.
       // Based on this CRA feature: https://github.com/facebookincubator/create-react-app/issues/253
       modules: ['node_modules'].concat(nodePaths),

lib/core/src/server/core-preset-dev.js

@@ -5,11 +5,11 @@ import createDevConfig from './config/webpack.config.dev';
 import defaultBabelConfig from './config/babel.dev';
 import { createManagerEntry, createPreviewEntry } from './config/entries';
 
-export function webpack(_, options) {
+export async function webpack(_, options) {
   return createDevConfig(options);
 }
 
-export function babel(_, options) {
+export async function babel(_, options) {
   const { configDir, presets } = options;
 
   return loadCustomBabelConfig(configDir, () =>
@@ -17,21 +17,20 @@ export function babel(_, options) {
   );
 }
 
-export function manager(_, options) {
+export async function manager(_, options) {
   return createManagerEntry(options);
 }
 
-export function preview(_, options) {
-  return [
-    ...createPreviewEntry(options),
-    `${require.resolve('webpack-hot-middleware/client')}?reload=true`,
-  ];
+export async function preview(_, options) {
+  const entry = await createPreviewEntry(options);
+
+  return [...entry, `${require.resolve('webpack-hot-middleware/client')}?reload=true`];
 }
 
-export function addons(_, options) {
+export async function addons(_, options) {
   return loadCustomAddons(options);
 }
 
-export function config(_, options) {
+export async function config(_, options) {
   return loadCustomConfig(options);
 }

lib/core/src/server/core-preset-prod.js

@@ -5,11 +5,11 @@ import createProdConfig from './config/webpack.config.prod';
 import defaultBabelConfig from './config/babel.prod';
 import { createManagerEntry, createPreviewEntry } from './config/entries';
 
-export function webpack(_, options) {
+export async function webpack(_, options) {
   return createProdConfig(options);
 }
 
-export function babel(_, options) {
+export async function babel(_, options) {
   const { configDir, presets } = options;
 
   return loadCustomBabelConfig(configDir, () =>
@@ -17,18 +17,18 @@ export function babel(_, options) {
   );
 }
 
-export function manager(_, options) {
+export async function manager(_, options) {
   return createManagerEntry(options);
 }
 
-export function preview(_, options) {
+export async function preview(_, options) {
   return createPreviewEntry(options);
 }
 
-export function addons(_, options) {
+export async function addons(_, options) {
   return loadCustomAddons(options);
 }
 
-export function config(_, options) {
+export async function config(_, options) {
   return loadCustomConfig(options);
 }

lib/core/src/server/loadCustomBabelConfig.js

@@ -53,7 +53,7 @@ function isBabelLoader8() {
   return satisfies(babelLoaderPkg.version, '>=8.0.0-0');
 }
 
-export default function(configDir, getDefaultConfig) {
+export default async function(configDir, getDefaultConfig) {
   const babelConfig = loadFromPath(path.resolve(configDir, '.babelrc'));
 
   if (babelConfig) {

lib/core/src/server/middleware.js

@@ -14,12 +14,12 @@ export const webpackValid = new Promise((resolve, reject) => {
   webpackReject = reject;
 });
 
-export default function(options) {
+export default async function(options) {
   const { configDir } = options;
 
   // Build the webpack configuration using the `getBaseConfig`
   // custom `.babelrc` file and `webpack.config.js` files
-  const config = loadConfig({
+  const config = await loadConfig({
     configType: 'DEVELOPMENT',
     corePresets: [require.resolve('./core-preset-dev.js')],
     ...options,

lib/core/src/server/presets.js

@@ -42,31 +42,36 @@ function loadPresets(presets) {
 }
 
 function applyPresets(presets, config, args = {}, extension) {
+  const presetResult = new Promise(resolve => resolve(config));
+
   if (!presets.length) {
-    return config;
+    return presetResult;
   }
 
-  return presets.reduce((accumulatedConfig, { preset, options }) => {
+  return presets.reduce((accumulationPromise, { preset, options }) => {
     const extensionFn = preset[extension];
 
     if (extensionFn && typeof extensionFn === 'function') {
-      const combinedOptions = {
-        ...args,
-        ...options,
+      const context = {
+        extensionFn,
+        preset,
+        combinedOptions: { ...args, ...options },
       };
 
-      return extensionFn.call(preset, accumulatedConfig, combinedOptions);
+      return accumulationPromise.then(newConfig =>
+        context.extensionFn.call(context.preset, newConfig, context.combinedOptions)
+      );
     }
 
-    return accumulatedConfig;
-  }, config);
+    return accumulationPromise;
+  }, presetResult);
 }
 
 function getPresets(presets) {
   const loadedPresets = loadPresets(presets);
 
   return {
-    apply: (extension, config, args) => applyPresets(loadedPresets, config, args, extension),
+    apply: async (extension, config, args) => applyPresets(loadedPresets, config, args, extension),
   };
 }
 

lib/core/src/server/presets.test.js

@@ -1,7 +1,7 @@
 function wrapPreset(basePresets) {
   return {
-    babel: (config, args) => basePresets.apply('babel', config, args),
-    webpack: (config, args) => basePresets.apply('webpack', config, args),
+    babel: async (config, args) => basePresets.apply('babel', config, args),
+    webpack: async (config, args) => basePresets.apply('webpack', config, args),
   };
 }
 
@@ -10,40 +10,46 @@ function mockPreset(name, mockPresetObject) {
 }
 
 describe('presets', () => {
-  it('does not throw when there is no preset file', () => {
+  it('does not throw when there is no preset file', async () => {
     const loadPresets = require.requireActual('./presets').default;
     let presets;
 
-    expect(() => {
+    async function testPresets() {
       presets = wrapPreset(loadPresets());
-      presets.webpack();
-      presets.babel();
-    }).not.toThrow();
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(presets).toBeDefined();
   });
 
-  it('does not throw when presets are empty', () => {
+  it('does not throw when presets are empty', async () => {
     const loadPresets = require.requireActual('./presets').default;
     const presets = wrapPreset(loadPresets([]));
 
-    expect(() => {
-      presets.webpack();
-      presets.babel();
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
   });
 
-  it('does not throw when preset can not be loaded', () => {
+  it('does not throw when preset can not be loaded', async () => {
     const loadPresets = require.requireActual('./presets').default;
     const presets = wrapPreset(loadPresets(['preset-foo']));
 
-    expect(() => {
-      presets.webpack({});
-      presets.babel();
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
   });
 
-  it('loads  and applies presets when they are declared as a string', () => {
+  it('loads  and applies presets when they are declared as a string', async () => {
     const mockPresetFooExtendWebpack = jest.fn();
     const mockPresetBarExtendBabel = jest.fn();
 
@@ -58,16 +64,18 @@ describe('presets', () => {
     const loadPresets = require.requireActual('./presets').default;
     const presets = wrapPreset(loadPresets(['preset-foo', 'preset-bar']));
 
-    expect(() => {
-      presets.webpack();
-      presets.babel();
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(mockPresetFooExtendWebpack).toBeCalled();
     expect(mockPresetBarExtendBabel).toBeCalled();
   });
 
-  it('loads  and applies presets when they are declared as an object without props', () => {
+  it('loads  and applies presets when they are declared as an object without props', async () => {
     const mockPresetFooExtendWebpack = jest.fn();
     const mockPresetBarExtendBabel = jest.fn();
 
@@ -82,16 +90,18 @@ describe('presets', () => {
     const loadPresets = require.requireActual('./presets').default;
     const presets = wrapPreset(loadPresets([{ name: 'preset-foo' }, { name: 'preset-bar' }]));
 
-    expect(() => {
-      presets.webpack();
-      presets.babel();
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(mockPresetFooExtendWebpack).toBeCalled();
     expect(mockPresetBarExtendBabel).toBeCalled();
   });
 
-  it('loads and applies presets when they are declared as an object with props', () => {
+  it('loads and applies presets when they are declared as an object with props', async () => {
     const mockPresetFooExtendWebpack = jest.fn();
     const mockPresetBarExtendBabel = jest.fn();
 
@@ -111,16 +121,18 @@ describe('presets', () => {
       ])
     );
 
-    expect(() => {
-      presets.webpack({});
-      presets.babel({});
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack({});
+      await presets.babel({});
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(mockPresetFooExtendWebpack).toBeCalledWith(expect.anything(), { foo: 1 });
     expect(mockPresetBarExtendBabel).toBeCalledWith(expect.anything(), { bar: 'a' });
   });
 
-  it('loads and applies  presets when they are declared as a string and as an object', () => {
+  it('loads and applies  presets when they are declared as a string and as an object', async () => {
     const mockPresetFooExtendWebpack = jest.fn();
     const mockPresetBarExtendBabel = jest.fn();
 
@@ -137,16 +149,18 @@ describe('presets', () => {
       loadPresets(['preset-foo', { name: 'preset-bar', options: { bar: 'a' } }])
     );
 
-    expect(() => {
-      presets.webpack({});
-      presets.babel({});
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack({});
+      await presets.babel({});
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(mockPresetFooExtendWebpack).toBeCalled();
     expect(mockPresetBarExtendBabel).toBeCalledWith(expect.anything(), { bar: 'a' });
   });
 
-  it('applies presets in chain', () => {
+  it('applies presets in chain', async () => {
     const mockPresetFooExtendWebpack = jest.fn(() => ({}));
     const mockPresetBarExtendWebpack = jest.fn(() => ({}));
 
@@ -163,10 +177,12 @@ describe('presets', () => {
       loadPresets(['preset-foo', { name: 'preset-bar', options: { bar: 'a' } }])
     );
 
-    expect(() => {
-      presets.webpack({});
-      presets.babel();
-    }).not.toThrow();
+    async function testPresets() {
+      await presets.webpack();
+      await presets.babel();
+    }
+
+    await expect(testPresets()).resolves.toBeUndefined();
 
     expect(mockPresetFooExtendWebpack).toBeCalled();
     expect(mockPresetBarExtendWebpack).toBeCalledWith(expect.anything(), { bar: 'a' });

yarn.lock

@@ -22750,10 +22750,10 @@ webpack@4.19.1:
     watchpack "^1.5.0"
     webpack-sources "^1.2.0"
 
-webpack@^4.15.1, webpack@^4.17.1, webpack@^4.20.2:
-  version "4.20.2"
-  resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.20.2.tgz#89f6486b6bb276a91b0823453d377501fc625b5a"
-  integrity sha512-75WFUMblcWYcocjSLlXCb71QuGyH7egdBZu50FtBGl2Nso8CK3Ej+J7bTZz2FPFq5l6fzCisD9modB7t30ikuA==
+webpack@^4.15.1, webpack@^4.21.0:
+  version "4.21.0"
+  resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.21.0.tgz#bd03605c0f48c0d4aaaef78ead2769485e5afd92"
+  integrity sha512-CGBeop4AYR0dcmk9Afl33qQULwTHQCXQPAIBTHMJoy9DpY8FPUDna/NUlAGTr5o5y9QC901Ww3wCY4wNo1X9Lw==
   dependencies:
     "@webassemblyjs/ast" "1.7.8"
     "@webassemblyjs/helper-module-context" "1.7.8"