---
layout: page
title: 将模板引擎用于 Express
description: Discover how to integrate and use template engines like Pug, Handlebars, and EJS with Express.js to render dynamic HTML pages efficiently.
menu: guide
order: 5
redirect_from: "  "
---

# 将模板引擎用于 Express

A _template engine_ enables you to use static template files in your application. At runtime, the template engine replaces
variables in a template file with actual values, and transforms the template into an HTML file sent to the client.
This approach makes it easier to design an HTML page.

The [Express application generator](/{{ page.lang }}/starter/generator.html) uses [Pug](https://pugjs.org/api/getting-started.html) as its default, but it also supports [Handlebars](https://www.npmjs.com/package/handlebars), and [EJS](https://www.npmjs.com/package/ejs), among others.

To render template files, set the following [application setting properties](/{{ page.lang }}/4x/api.html#app.set), in the default `app.js` created by the generator:

- `views`, the directory where the template files are located. `views`：模板文件所在目录。例如：`app.set('views', './views')`
  This defaults to the `views` directory in the application root directory.
- `view engine`, the template engine to use. `view engine`：要使用的模板引擎。例如：`app.set('view engine', 'pug')`

然后安装对应的模板引擎 npm 包：

```bash
$ npm install pug --save
```

<div class="doc-box doc-notice" markdown="1">
与 Express 兼容的模板引擎（例如 Pug）导出名为 `__express(filePath, options, callback)` 的函数，该函数由 `res.render()` 函数调用以呈现模板代码。
某些模板引擎并不遵循此约定。[Consolidate.js](https://www.npmjs.org/package/consolidate) 库通过映射所有流行的 Node.js 模板引擎来遵循此约定，因此可以在 Express 内无缝工作。


Some template engines do not follow this convention. The [@ladjs/consolidate](https://www.npmjs.com/package/@ladjs/consolidate)
library follows this convention by mapping all of the popular Node.js template engines, and therefore works seamlessly within Express.

</div>

在设置视图引擎之后，不必指定该引擎或者在应用程序中装入模板引擎模块；Express 在内部装入此模块，如下所示（针对以上示例）。

```js
app.set('view engine', 'pug')
```

在 `views` 目录中创建名为 `index.pug` 的 Pug 模板文件，其中包含以下内容：

```pug
html
  head
    title= title
  body
    h1= message
```

Create a route to render the `index.pug` file. If the `view engine` property is not set,
you must specify the extension of the `view` file. Otherwise, you can omit it.

```js
app.get('/', (req, res) => {
  res.render('index', { title: 'Hey', message: 'Hello there!' })
})
```

向主页发出请求时，`index.pug` 文件将呈现为 HTML。

The view engine cache does not cache the contents of the template's output, only the underlying template itself. The view is still re-rendered with every request even when the cache is on.
