Node.js Express报错：未指定默认模板引擎且未提供扩展名

报错信息 #

Error: No default engine was specified and no extension was provided.
    at new View (D:\Coding\pizza\node_modules\express\lib\view.js:61:11)
    at Function.render (D:\Coding\pizza\node_modules\express\lib\application.js:587:12)
    at ServerResponse.render (D:\Coding\pizza\node_modules\express\lib\response.js:1039:7)
    at D:\Coding\pizza\server.js:9:9
    at Layer.handle [as handle_request] (D:\Coding\pizza\node_modules\express\lib\router\layer.js:95:5)
    at next (D:\Coding\pizza\node_modules\express\lib\router\route.js:144:13)
    at Route.dispatch (D:\Coding\pizza\node_modules\express\lib\router\route.js:114:3)
    at Layer.handle [as handle_request] (D:\Coding\pizza\node_modules\express\lib\router\layer.js:95:5)
    at D:\Coding\pizza\node_modules\express\lib\router\index.js:284:15
    at Function.process_params (D:\Coding\pizza\node_modules\express\lib\router\index.js:346:12)

服务器配置代码 #

const express = require('express')
const app = express()
const ejs = require('ejs')
const path = require('path')
const expressLayout = require ('express-ejs-layouts')
const PORT = process.env.PORT || 3000

app.get('/', (req, res)=> {
    res.render('home')
})

//set template engine
app.use(expressLayout)
app.set('views',path.join(__dirname, '/resources/views'))
app.set('view-engine','ejs')

app.listen(PORT, () => {
console.log(`Listening on port ${PORT}`)
})

预期页面输出：Hello from home Page

问题原因及解决办法 #

报错有两个核心原因：

1. 路由定义顺序错误：模板引擎配置在路由之后，导致Express处理请求时还未加载引擎配置，无法识别渲染规则。
2. 引擎设置键名错误：Express中设置视图引擎的正确键名是view engine（空格分隔），而非view-engine（横杠分隔）。

修改后的代码 #

const express = require('express')
const app = express()
const ejs = require('ejs')
const path = require('path')
const expressLayout = require ('express-ejs-layouts')
const PORT = process.env.PORT || 3000

// 先配置模板引擎
app.use(expressLayout)
app.set('views', path.join(__dirname, '/resources/views'))
app.set('view engine', 'ejs') // 修正键名

// 再定义路由
app.get('/', (req, res)=> {
    res.render('home')
})

app.listen(PORT, () => {
    console.log(`Listening on port ${PORT}`)
})

额外验证 #

确保resources/views目录下存在home.ejs文件，内容为：

Hello from home Page

内容的提问来源于stack exchange，提问作者Sundaram