Move plugins and loaders to webpack folder (#4618)

Also adds basic `flow` to webpack.js and the plugins.

build/webpack.js

@@ -1,3 +1,5 @@
+// @flow
+import type {NextConfig} from '../server/config'
 import path, {sep} from 'path'
 import webpack from 'webpack'
 import resolve from 'resolve'
@@ -6,12 +8,12 @@ import CaseSensitivePathPlugin from 'case-sensitive-paths-webpack-plugin'
 import WriteFilePlugin from 'write-file-webpack-plugin'
 import FriendlyErrorsWebpackPlugin from 'friendly-errors-webpack-plugin'
 import {getPages} from './webpack/utils'
-import PagesPlugin from './plugins/pages-plugin'
-import NextJsSsrImportPlugin from './plugins/nextjs-ssr-import'
-import DynamicChunksPlugin from './plugins/dynamic-chunks-plugin'
-import UnlinkFilePlugin from './plugins/unlink-file-plugin'
-import PagesManifestPlugin from './plugins/pages-manifest-plugin'
-import BuildManifestPlugin from './plugins/build-manifest-plugin'
+import PagesPlugin from './webpack/plugins/pages-plugin'
+import NextJsSsrImportPlugin from './webpack/plugins/nextjs-ssr-import'
+import DynamicChunksPlugin from './webpack/plugins/dynamic-chunks-plugin'
+import UnlinkFilePlugin from './webpack/plugins/unlink-file-plugin'
+import PagesManifestPlugin from './webpack/plugins/pages-manifest-plugin'
+import BuildManifestPlugin from './webpack/plugins/build-manifest-plugin'
 import {SERVER_DIRECTORY, NEXT_PROJECT_ROOT, NEXT_PROJECT_ROOT_NODE_MODULES, NEXT_PROJECT_ROOT_DIST, DEFAULT_PAGES_DIR} from '../lib/constants'
 
 function externalsConfig (dir, isServer) {
@@ -48,7 +50,14 @@ function externalsConfig (dir, isServer) {
   return externals
 }
 
-export default async function getBaseWebpackConfig (dir, {dev = false, isServer = false, buildId, config}) {
+type BaseConfigContext = {|
+  dev: boolean,
+  isServer: boolean,
+  buildId: string,
+  config: NextConfig
+|}
+
+export default async function getBaseWebpackConfig (dir: string, {dev = false, isServer = false, buildId, config}: BaseConfigContext) {
   const defaultLoaders = {
     babel: {
       loader: 'next-babel-loader',
@@ -121,7 +130,7 @@ export default async function getBaseWebpackConfig (dir, {dev = false, isServer
       modules: [
         NEXT_PROJECT_ROOT_NODE_MODULES,
         'node_modules',
-        path.join(__dirname, 'loaders'),
+        path.join(__dirname, 'webpack', 'loaders'), // The loaders Next.js provides
         ...nodePathList // Support for NODE_PATH environment variable
       ]
     },

build/webpack/loaders/next-babel-loader.js

@@ -1,7 +1,7 @@
 import babelLoader from 'babel-loader'
 
 module.exports = babelLoader.custom(babel => {
-  const presetItem = babel.createConfigItem(require('../babel/preset'), {type: 'preset'})
+  const presetItem = babel.createConfigItem(require('../../babel/preset'), {type: 'preset'})
   const reactJsxSourceItem = babel.createConfigItem(require('@babel/plugin-transform-react-jsx-source'), {type: 'plugin'})
 
   const configs = new Set()

build/webpack/plugins/build-manifest-plugin.js

@@ -1,6 +1,6 @@
 // @flow
 import { RawSource } from 'webpack-sources'
-import {BUILD_MANIFEST} from '../../lib/constants'
+import {BUILD_MANIFEST} from '../../../lib/constants'
 
 // This plugin creates a build-manifest.json for all assets that are being output
 // It has a mapping of "entry" filename to real filename. Because the real filename can be hashed in production

build/webpack/plugins/pages-manifest-plugin.js

@@ -1,6 +1,6 @@
 // @flow
 import { RawSource } from 'webpack-sources'
-import {PAGES_MANIFEST, ROUTE_NAME_REGEX} from '../../lib/constants'
+import {PAGES_MANIFEST, ROUTE_NAME_REGEX} from '../../../lib/constants'
 
 // This plugin creates a pages-manifest.json from page entrypoints.
 // This is used for mapping paths like `/` to `.next/dist/bundles/pages/index.js` when doing SSR

build/webpack/plugins/pages-plugin.js

@@ -1,8 +1,9 @@
+// @flow
 import { ConcatSource } from 'webpack-sources'
 import {
   IS_BUNDLED_PAGE_REGEX,
   ROUTE_NAME_REGEX
-} from '../../lib/constants'
+} from '../../../lib/constants'
 
 class PageChunkTemplatePlugin {
   apply (chunkTemplate) {
@@ -42,7 +43,7 @@ class PageChunkTemplatePlugin {
 }
 
 export default class PagesPlugin {
-  apply (compiler) {
+  apply (compiler: any) {
     compiler.plugin('compilation', (compilation) => {
       compilation.chunkTemplate.apply(new PageChunkTemplatePlugin())
     })

build/webpack/plugins/unlink-file-plugin.js

@@ -1,16 +1,18 @@
+// @flow
 import { join } from 'path'
-import promisify from '../../lib/promisify'
+import promisify from '../../../lib/promisify'
 import fs from 'fs'
-import { IS_BUNDLED_PAGE_REGEX } from '../../lib/constants'
+import { IS_BUNDLED_PAGE_REGEX } from '../../../lib/constants'
 
 const unlink = promisify(fs.unlink)
 
 export default class UnlinkFilePlugin {
+  prevAssets: any
   constructor () {
     this.prevAssets = {}
   }
 
-  apply (compiler) {
+  apply (compiler: any) {
     compiler.plugin('after-emit', (compilation, callback) => {
       const removed = Object.keys(this.prevAssets)
         .filter((a) => IS_BUNDLED_PAGE_REGEX.test(a) && !compilation.assets[a])

flow-typed/npm/uglifyjs-webpack-plugin_vx.x.x.js

@@ -0,0 +1,67 @@
+// flow-typed signature: e7e7f59f1cdd9c963584b4620763fec3
+// flow-typed version: <<STUB>>/uglifyjs-webpack-plugin_v1.1.6/flow_v0.73.0
+
+/**
+ * This is an autogenerated libdef stub for:
+ *
+ *   'uglifyjs-webpack-plugin'
+ *
+ * Fill this stub out by replacing all the `any` types.
+ *
+ * Once filled out, we encourage you to share your work with the
+ * community by sending a pull request to:
+ * https://github.com/flowtype/flow-typed
+ */
+
+declare module 'uglifyjs-webpack-plugin' {
+  declare module.exports: any;
+}
+
+/**
+ * We include stubs for each file inside this npm package in case you need to
+ * require those files directly. Feel free to delete any files that aren't
+ * needed.
+ */
+declare module 'uglifyjs-webpack-plugin/dist/cjs' {
+  declare module.exports: any;
+}
+
+declare module 'uglifyjs-webpack-plugin/dist/index' {
+  declare module.exports: any;
+}
+
+declare module 'uglifyjs-webpack-plugin/dist/uglify/index' {
+  declare module.exports: any;
+}
+
+declare module 'uglifyjs-webpack-plugin/dist/uglify/minify' {
+  declare module.exports: any;
+}
+
+declare module 'uglifyjs-webpack-plugin/dist/uglify/versions' {
+  declare module.exports: any;
+}
+
+declare module 'uglifyjs-webpack-plugin/dist/uglify/worker' {
+  declare module.exports: any;
+}
+
+// Filename aliases
+declare module 'uglifyjs-webpack-plugin/dist/cjs.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/cjs'>;
+}
+declare module 'uglifyjs-webpack-plugin/dist/index.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/index'>;
+}
+declare module 'uglifyjs-webpack-plugin/dist/uglify/index.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/uglify/index'>;
+}
+declare module 'uglifyjs-webpack-plugin/dist/uglify/minify.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/uglify/minify'>;
+}
+declare module 'uglifyjs-webpack-plugin/dist/uglify/versions.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/uglify/versions'>;
+}
+declare module 'uglifyjs-webpack-plugin/dist/uglify/worker.js' {
+  declare module.exports: $Exports<'uglifyjs-webpack-plugin/dist/uglify/worker'>;
+}

flow-typed/npm/write-file-webpack-plugin_vx.x.x.js

@@ -0,0 +1,32 @@
+// flow-typed signature: 4a61661df41490b27db4f4aa0c03929e
+// flow-typed version: <<STUB>>/write-file-webpack-plugin_v4.2.0/flow_v0.73.0
+
+/**
+ * This is an autogenerated libdef stub for:
+ *
+ *   'write-file-webpack-plugin'
+ *
+ * Fill this stub out by replacing all the `any` types.
+ *
+ * Once filled out, we encourage you to share your work with the
+ * community by sending a pull request to:
+ * https://github.com/flowtype/flow-typed
+ */
+
+declare module 'write-file-webpack-plugin' {
+  declare module.exports: any;
+}
+
+/**
+ * We include stubs for each file inside this npm package in case you need to
+ * require those files directly. Feel free to delete any files that aren't
+ * needed.
+ */
+declare module 'write-file-webpack-plugin/dist/index' {
+  declare module.exports: any;
+}
+
+// Filename aliases
+declare module 'write-file-webpack-plugin/dist/index.js' {
+  declare module.exports: $Exports<'write-file-webpack-plugin/dist/index'>;
+}