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next.js/server/hot-reloader.js
2016-12-21 06:39:08 -08:00

226 lines
6 KiB
JavaScript

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 babel, { watch } from './build/babel'
import read from './read'
export default class HotReloader {
constructor (dir, { quiet } = {}) {
this.dir = dir
this.quiet = quiet
this.middlewares = []
this.webpackDevMiddleware = null
this.webpackHotMiddleware = null
this.watcher = 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) reject(err)
resolve()
})
})
}
}
async start () {
this.watch()
const [compiler] = await Promise.all([
webpack(this.dir, { dev: true, quiet: this.quiet }),
clean(this.dir)
])
await Promise.all([
this.prepareMiddlewares(compiler),
babel(this.dir, { dev: true })
])
this.stats = await this.waitUntilValid()
}
async stop () {
if (this.watcher) this.watcher.close()
if (this.webpackDevMiddleware) {
return new Promise((resolve, reject) => {
this.webpackDevMiddleware.close((err) => {
if (err) 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',
...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 })
}
watch () {
const onChange = (path) => {
babel(this.dir, { dev: true })
.then(() => {
const f = join(this.dir, '.next', 'dist', relative(this.dir, path))
delete require.cache[f]
this.send('hardReload')
})
}
this.watcher = watch(this.dir)
this.watcher
.on('add', onChange)
.on('change', onChange)
.on('unlink', onChange)
.on('error', (err) => {
console.error(err)
})
}
}
function deleteCache (path) {
delete require.cache[path]
delete read.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$/, '') || '/'
}