feat: vite-node watch mode

examples/vite-node/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "vitest-test",
+  "private": true,
+  "main": "index.js",
+  "license": "MIT",
+  "type": "module",
+  "scripts": {
+    "start": "vite-node --watch ./src/*"
+  },
+  "devDependencies": {
+    "vite-node": "latest"
+  },
+  "stackblitz": {
+    "startCommand": "npm run start"
+  }
+}

examples/vite-node/src/index.js

@@ -0,0 +1,6 @@
+/* eslint-disable no-console */
+import { a } from './testModule'
+
+console.log('[index.js] load!')
+console.log('hello worlds')
+console.log(a)

examples/vite-node/src/testModule.js

@@ -0,0 +1,4 @@
+export const a = 'hello testModule'
+
+// eslint-disable-next-line no-console
+console.log('[testModule.js] load!')

examples/vite-node/vite.config.ts

@@ -0,0 +1,12 @@
+/// <reference types="vitest" />
+
+// Configure Vitest (https://vitest.dev/config)
+
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  test: {
+    /* for example, use global to avoid globals imports (describe, test, expect): */
+    // globals: true,
+  },
+})

packages/vite-node/src/cli.ts

@@ -1,8 +1,12 @@
+import EventEmitter from 'events'
 import minimist from 'minimist'
 import { dim, red } from 'kolorist'
+import type { ModuleNode } from 'vite'
 import { createServer } from 'vite'
 import { ViteNodeServer } from './server'
 import { ViteNodeRunner } from './client'
+import { viteNodeHmrPlugin } from './hmr'
+import { slash } from './utils'
 
 const argv = minimist(process.argv.slice(2), {
   'alias': {
@@ -61,16 +65,20 @@ export interface CliOptions {
   _?: string[]
   root?: string
   config?: string
+  watch?: boolean
 }
 
 async function run(options: CliOptions = {}) {
   const files = options.files || options._ || []
-
+  const event = new EventEmitter()
   const server = await createServer({
     logLevel: 'error',
     clearScreen: false,
     configFile: options.config,
     root: options.root,
+    plugins: [
+      options.watch && viteNodeHmrPlugin(event),
+    ],
   })
   await server.pluginContainer.buildStart({})
 
@@ -93,5 +101,27 @@ async function run(options: CliOptions = {}) {
   for (const file of files)
     await runner.executeFile(file)
 
-  await server.close()
+  if (!options.watch)
+    await server.close()
+
+  event.on('updateModules', (modules: ModuleNode[]) => {
+    walkModules(modules, (module) => {
+      const { file, url } = module
+      const id = `/@fs/${slash(file!)}`
+      runner.moduleCache.delete(url)
+      runner.moduleCache.delete(id)
+      runner.executeId(id)
+    })
+  })
+}
+
+function walkModules(modules: ModuleNode[], cb: (module: ModuleNode) => void, seen?: Set<string>) {
+  seen ||= new Set()
+  modules.forEach((module) => {
+    if (!seen!.has(module.file!)) {
+      seen?.add(module.file!)
+      cb(module)
+    }
+    walkModules([...module.importers], cb, seen)
+  })
 }

packages/vite-node/src/hmr.ts

@@ -0,0 +1,20 @@
+import type { EventEmitter } from 'events'
+import type { Plugin, ViteDevServer } from 'vite'
+
+export function viteNodeHmrPlugin(event: EventEmitter): Plugin {
+  let server: ViteDevServer
+  return {
+    name: 'vite-node-hmr',
+
+    configureServer(_server) {
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
+      server = _server
+    },
+
+    handleHotUpdate(ctx) {
+      const { modules } = ctx
+      event.emit('updateModules', modules)
+      return modules
+    },
+  }
+}