老师，我在执行 npm start 后出现如下错误

Error: Cannot find module '../../public/vue-ssr-client-manifest.json'

    at Function.Module._resolveFilename (module.js:547:15)

    at Function.Module._load (module.js:474:25)

    at Module.require (module.js:596:17)

    at require (internal/module.js:11:18)

    at Object.<anonymous> (D:\projects\Vue+Vue-Router+Vuex+SSR\vue-todo-tech\server\routers\ssr.js:8:24)

    at Module._compile (module.js:652:30)

    at Object.Module._extensions..js (module.js:663:10)

    at Module.load (module.js:565:32)

    at tryModuleLoad (module.js:505:12)

    at Function.Module._load (module.js:497:3)

出错位置在：ssr.js

const clientManifest = require('../../public/vue-ssr-client-manifest.json')

在执行 npm run build 后，在public目录下没有vue-ssr-client-manifest.json文件

public目录如下结构：（public目录下除了以下目录和文件没有其他）

-public

    -resources

    -app.[hash].js

    -runtime.[hash].js

    -styles.[hash].js

    -vendor.[hash].js

package.json的配置：

"build:client": "cross-env NODE_ENV=production webpack --config build/webpack.config.client.js",

"build:server": "cross-env NODE_ENV=production webpack --config build/webpack.config.server.js",

"build": "npm run clean && npm run build:client && npm run build:server",

"dev:client": "cross-env NODE_ENV=development webpack-dev-server --config build/webpack.config.client.js",

"dev:server": "nodemon server/server.js",

"dev": "concurrently \"npm run dev:client\" \"npm run dev:server\"",

"start": "cross-env NODE_ENV=production node server/server.js"

请老师帮我解答

注：

在执行 npm run dev是 http://localhost:3333/app 和 http://localhost:8000/app 都可以正常访问