feat: support preload script hot reload

script/build-preload.ts

@@ -2,7 +2,9 @@ import { watch, rollup, OutputOptions } from 'rollup'
 import minimist from 'minimist'
 import chalk from 'chalk'
 import ora from 'ora'
+import WebSocket from 'ws'
 import options from './rollup.config'
+import { createWsServer, formatWsSendData } from './ws'
 
 const argv = minimist(process.argv.slice(2))
 const opt = options({ proc: 'preload', env: argv.env })
@@ -12,13 +14,17 @@ const spinner = ora(`${TAG} Electron preload build...`)
 ; (async () => {
   if (argv.watch) {
     const watcher = watch(opt)
+    const wssObj = createWsServer({ TAG })
+
     watcher.on('change', filename => {
       const log = chalk.yellow(`change -- ${filename}`)
       console.log(TAG, log)
 
-      /**
-       * @todo Hot reload render process !!!
-       */
+      // Hot reload renderer process !!!
+      if (wssObj.instance?.readyState === WebSocket.OPEN) {
+        console.log(TAG, 'Hot reload renderer process')
+        wssObj.instance.send(formatWsSendData({ cmd: 'reload', data: Date.now() }))
+      }
     })
   } else {
     spinner.start()

script/ws.ts

@@ -0,0 +1,43 @@
+/**
+ * Hot reload from preload script during development
+ */
+import WebSocket from 'ws'
+import chalk from 'chalk'
+import pkg from '../package.json'
+
+export interface CreateWsServerOptions {
+  TAG: string
+}
+
+export function createWsServer(options: CreateWsServerOptions) {
+  const { TAG } = options
+  const port = pkg.env.PORT_WS
+  const host = '127.0.0.1'
+  const wss = new WebSocket.Server({ host, port })
+  const wssObj: { wss: WebSocket.Server; instance: WebSocket | null } = { wss, instance: null }
+
+  console.log(TAG, 'Wss run at - ' + chalk.yellow(`ws://${host}:${port}`))
+
+  wss.on('connection', ws => {
+    console.log(TAG, chalk.yellow(`wss.on('connection')`))
+
+    wssObj.instance = ws
+    ws.on('message', message => {
+      console.log(TAG, `ws.on('message'):`, message.toString())
+    })
+
+    ws.send(formatWsSendData({ cmd: 'message', data: 'connected.' }))
+  })
+
+  wss.on('close', () => {
+    console.log(TAG, chalk.gray(`wss.on('close')`))
+
+    wssObj.instance = null
+  })
+
+  return wssObj
+}
+
+export function formatWsSendData(json: { cmd: string, data?: any }) {
+  return JSON.stringify(json)
+}