import { join, relative, sep } from 'path' import webpackDevMiddleware from 'webpack-dev-middleware' import webpackHotMiddleware from 'webpack-hot-middleware' import isWindowsBash from 'is-windows-bash' import webpack from './build/webpack' import clean from './build/clean' import readPage from './read-page' export default class HotReloader { constructor (dir, { quiet } = {}) { this.dir = dir this.quiet = quiet this.middlewares = [] this.webpackDevMiddleware = null this.webpackHotMiddleware = null this.initialized = false this.stats = null this.compilationErrors = null this.prevAssets = null this.prevChunkNames = null this.prevFailedChunkNames = null this.prevChunkHashes = null } async run (req, res) { for (const fn of this.middlewares) { await new Promise((resolve, reject) => { fn(req, res, (err) => { if (err) return reject(err) resolve() }) }) } } async start () { const [compiler] = await Promise.all([ webpack(this.dir, { dev: true, quiet: this.quiet }), clean(this.dir) ]) this.prepareMiddlewares(compiler) this.stats = await this.waitUntilValid() } async stop () { if (this.webpackDevMiddleware) { return new Promise((resolve, reject) => { this.webpackDevMiddleware.close((err) => { if (err) return reject(err) resolve() }) }) } } async prepareMiddlewares (compiler) { compiler.plugin('after-emit', (compilation, callback) => { const { assets } = compilation if (this.prevAssets) { for (const f of Object.keys(assets)) { deleteCache(assets[f].existsAt) } for (const f of Object.keys(this.prevAssets)) { if (!assets[f]) { deleteCache(this.prevAssets[f].existsAt) } } } this.prevAssets = assets callback() }) compiler.plugin('done', (stats) => { const { compilation } = stats const chunkNames = new Set(compilation.chunks.map((c) => c.name)) const failedChunkNames = new Set(compilation.errors .map((e) => e.module.reasons) .reduce((a, b) => a.concat(b), []) .map((r) => r.module.chunks) .reduce((a, b) => a.concat(b), []) .map((c) => c.name)) const chunkHashes = new Map(compilation.chunks.map((c) => [c.name, c.hash])) if (this.initialized) { // detect chunks which have to be replaced with a new template // e.g, pages/index.js <-> pages/_error.js const added = diff(chunkNames, this.prevChunkNames) const removed = diff(this.prevChunkNames, chunkNames) const succeeded = diff(this.prevFailedChunkNames, failedChunkNames) // reload all failed chunks to replace the templace to the error ones, // and to update error content const failed = failedChunkNames const rootDir = join('bundles', 'pages') for (const n of new Set([...added, ...removed, ...failed, ...succeeded])) { const route = toRoute(relative(rootDir, n)) this.send('reload', route) } for (const [n, hash] of chunkHashes) { if (!this.prevChunkHashes.has(n)) continue if (this.prevChunkHashes.get(n) === hash) continue const route = toRoute(relative(rootDir, n)) // notify change to recover from runtime errors this.send('change', route) } } this.initialized = true this.stats = stats this.compilationErrors = null this.prevChunkNames = chunkNames this.prevFailedChunkNames = failedChunkNames this.prevChunkHashes = chunkHashes }) const windowsSettings = isWindowsBash() ? { lazy: false, watchOptions: { aggregateTimeout: 300, poll: true } } : {} this.webpackDevMiddleware = webpackDevMiddleware(compiler, { publicPath: '/_webpack/', noInfo: true, quiet: true, clientLogLevel: 'warning', watchOptions: { ignored: [ /(^|[/\\])\../, // .dotfiles /node_modules/ ] }, ...windowsSettings }) this.webpackHotMiddleware = webpackHotMiddleware(compiler, { log: false }) this.middlewares = [ this.webpackDevMiddleware, this.webpackHotMiddleware ] } waitUntilValid () { return new Promise((resolve) => { this.webpackDevMiddleware.waitUntilValid(resolve) }) } getCompilationErrors () { if (!this.compilationErrors) { this.compilationErrors = new Map() if (this.stats.hasErrors()) { const { compiler, errors } = this.stats.compilation for (const err of errors) { for (const r of err.module.reasons) { for (const c of r.module.chunks) { // get the path of the bundle file const path = join(compiler.outputPath, c.name) const errors = this.compilationErrors.get(path) || [] this.compilationErrors.set(path, errors.concat([err])) } } } } } return this.compilationErrors } send (action, ...args) { this.webpackHotMiddleware.publish({ action, data: args }) } } function deleteCache (path) { delete require.cache[path] delete readPage.cache[path] } function diff (a, b) { return new Set([...a].filter((v) => !b.has(v))) } function toRoute (file) { const f = sep === '\\' ? file.replace(/\\/g, '/') : file return ('/' + f).replace(/(\/index)?\.js$/, '') || '/' }