node nodemon_如何使用nodemon自动重启Node.js应用

电玩女神 2022-11-28 15:21 230阅读 0赞

node nodemon

### 介绍 **(**Introduction**)** ###

In Node.js, you need to restart the process to make changes take effect. This adds an extra step to your workflow to have the changes take place. You can eliminate this extra step by using `nodemon` to restart the process automatically.

在Node.js中，您需要重新启动过程以使更改生效。 这为工作流程增加了一个额外的步骤，以使更改生效。 您可以通过使用`nodemon`自动重新启动该过程来消除此额外步骤。

[`nodemon`][nodemon] is a command-line interface (CLI) utility developed by [@rem][rem] that wraps your Node app, watches the file system, and automatically restarts the process.

[`nodemon`][nodemon]是由[@rem][rem]开发的命令行界面(CLI)实用程序，用于包装您的Node应用程序， [`nodemon`][nodemon]文件系统并自动重新启动该过程。

In this article, you will learn about installing, setting up, and configuring `nodemon`.

在本文中，您将学习有关安装，设置和配置`nodemon` 。

## 先决条件 **(**Prerequisites**)** ##

If you would like to follow along with this article, you will need:

如果您想继续阅读本文，则需要：

*  Node.js installed locally, which you can do by following [How to Install Node.js and Create a Local Development Environment][].
    
    Node.js在本地安装，您可以按照[如何安装Node.js和创建本地开发环境进行操作][How to Install Node.js and Create a Local Development Environment] 。

## 第1步-安装`nodemon` **(**Step 1 — Installing `nodemon`**)** ##

First, you will need to install `nodemon` on your machine. Install the utility either globally or locally on your project using [npm or Yarn][]:

首先，您将需要在`nodemon`上安装`nodemon` 。 使用[npm或Yarn][npm or Yarn]在您的项目中全局或本地安装实用程序：

### 全局安装 **(**Global Installation**)** ###

You can install `nodemon` globally with `npm`:

您可以使用`npm`全局安装`nodemon` ：

*  npm install nodemon -g
    
    npm安装nodemon -g

Or with Yarn:

或使用纱线：

*  yarn global add nodemon
    
    纱线全局添加节点

### 本地安装 **(**Local Installation**)** ###

You can also install `nodemon` locally with npm. When performing a local installation, we can install `nodemon` as a [dev dependency][] with `--save-dev` (or `--dev`):

您也可以使用npm在本地安装`nodemon` 。 执行本地安装时，我们可以使用`--save-dev` (或`--dev` )将`nodemon`安装为[dev依赖][dev dependency] `--dev` ：

*  npm install nodemon --save-dev
    
    npm install nodemon --save-dev

Or with Yarn:

或使用纱线：

*  yarn add nodemon --dev
    
    纱线添加nodemon --dev

One thing to be aware of with a local install is you won’t be able to use the `nodemon` command directly from the command line:

本地安装要注意的一件事是，您将无法直接从命令行使用`nodemon`命令：

Output

输出量

*  command not found: nodemon
    
    找不到命令：nodemon

However, you can use it as part of some [npm scripts][] or with [npx][].

但是，您可以将其用作某些[npm脚本的][npm scripts]一部分或与[npx][]一起[使用][npx] 。

This concludes the `nodemon` installation process. Next, we will use `nodemon` with our projects.

到此结束`nodemon`安装过程。 接下来，我们将在项目中使用`nodemon` 。

## 第2步—使用`nodemon`设置示例Express项目 **(**Step 2 — Setting Up an Example Express Project with `nodemon`**)** ##

We can use `nodemon` to start a Node script. For example, if we have an [Express server setup][] in a `server.js` file, we can start it and watch for changes like this:

我们可以使用`nodemon`启动Node脚本。 例如，如果我们在`server.js`文件中有一个[Express服务器设置][Express server setup] ，则可以启动它并注意以下更改：

*  nodemon server.js
    
    nodemon server.js

You can pass in arguments the same way as if you were running the script with Node:

您可以通过与使用Node运行脚本相同的方式传递参数：

*  nodemon server.js 3006
    
    nodemon server.js 3006

Every time you make a change to a file with one of the default watched extensions (`.js`, `.mjs`, `.json`, `.coffee`, or `.litcoffee`) in the current directory or a subdirectory, the process will restart.

您更改与默认观看扩展(的一个文件每次`.js` ， `.mjs` ， `.json` ， `.coffee` ，或`.litcoffee` )在当前目录或子目录，该进程将重新启动。

Let’s assume we write an example `server.js` file that outputs the message: `Dolphin app listening on port ${port}!`.

假设我们编写了一个示例`server.js`文件，该文件输出以下消息： `Dolphin app listening on port ${port}!` 。

We can run the example with `nodemon`:

我们可以使用`nodemon`运行示例：

*  nodemon server.js
    
    nodemon server.js

We see the following terminal output:

我们看到以下终端输出：

Output [nodemon] 1.17.3
    [nodemon] to restart at any time, enter `rs`
    [nodemon] watching: *.*
    [nodemon] starting  `node server.js`
    Dolphin app listening on port 3000!

While `nodemon` is still running, let’s make a change to the `server.js` file to output the message: `Shark app listening on port ${port}!`.

当`nodemon`仍在运行时，让我们对`server.js`文件进行更改以输出以下消息： `Shark app listening on port ${port}!` 。

We see the following additional terminal output:

我们看到以下附加终端输出：

Output [nodemon] restarting due to changes...
    [nodemon] starting `node server.js`
    Shark app listening on port 3000!

The terminal output from our Node.js app is displaying as expected. You can restart the process at any time by typing `rs` and hitting `ENTER`.

Node.js应用程序的终端输出将按预期显示。 您可以随时输入`rs` `ENTER`来重新启动该过程。

Alternatively, `nodemon` will also look for a `main` file specified in your project’s `package.json` file:

另外， `nodemon`还将在项目的`package.json`文件中查找指定的`main`文件：

package.json

{
      // ...
      "main": "server.js",
      // ...
    }

Or, a `start` script:

或者，一个`start`脚本：

package.json

{
      // ...
      "scripts": {
        "start": "node server.js"
      },
      // ...
    }

Once you make the changes to `package.json`, you can then call `nodemon` to start the example app in watch mode without having to pass in `server.js`.

对`package.json`进行更改后，您可以调用`nodemon`以监视模式启动示例应用程序，而无需传入`server.js` 。

## 步骤3 —使用选项 **(**Step 3 — Using Options**)** ##

You can modify the configuration settings available to `nodemon`.

您可以修改可用于`nodemon`的配置设置。

Let’s go over a few of the main options:

让我们来看一些主要选项：

*  `--exec`: Use the `--exec` switch to specify a binary to execute the file with. For example, when combined with the [`ts-node`][ts-node] binary, `--exec` can become useful to watch for changes and run TypeScript files.
    
    `--exec` ：使用`--exec`开关指定执行文件的二进制文件。 例如，当与[`ts-node`][ts-node]二进制文件结合使用时，-- `--exec`可以用于监视更改和运行TypeScript文件。
 *  `--ext`: Specify different file extensions to watch. For this switch, provide a comma-separated list of file extensions (e.g., `--ext js,ts`).
    
    `--ext` ：指定要观看的其他文件扩展名。 对于此开关，请提供以逗号分隔的文件扩展名列表(例如`--ext js,ts` )。
 *  `--delay`: By default, `nodemon` waits for one second to restart the process when a file changes, but with the `--delay` switch, you can specify a different delay. For example, `nodemon --delay 3.2` for a 3.2-second delay.
    
    `--delay` ：默认情况下，当文件更改时， `nodemon`等待一秒钟以重新启动该过程，但是使用`--delay`开关，您可以指定其他延迟。 例如， `nodemon --delay 3.2`表示3.2秒的延迟。
 *  `--watch`: Use the `--watch` switch to specify multiple directories or files to watch. Add one `--watch` switch for each directory you want to watch. By default, the current directory and its subdirectories are watched, so with `--watch` you can narrow that to only specific subdirectories or files.
    
    `--watch` ：使用`--watch`开关指定要监视的多个目录或文件。 为要观看的每个目录添加一个`--watch`开关。 默认情况下，将监视当前目录及其子目录，因此使用`--watch`可以将其范围缩小到特定的子目录或文件。
 *  `--ignore`: Use the `--ignore` switch to ignore certain files, file patterns, or directories.
    
    `--ignore` ：使用`--ignore`开关可忽略某些文件，文件模式或目录。
 *  `--verbose`: A more verbose output with information about what file(s) changed to trigger a restart.
    
    `--verbose` ：更详细的输出，其中包含有关更改了哪些文件以触发重新启动的信息。

You can view all the available options with the following command:

您可以使用以下命令查看所有可用选项：

*  nodemon --help
    
    nodemon-帮助

Using these options, let’s create the command to satisfy the following scenario:

使用这些选项，让我们创建命令来满足以下情况：

*  watching the `server` directory
    
    查看`server`目录
 *  specifying files with a `.ts` extension
    
    指定扩展名为`.ts`文件
 *  ignoring files with a `.test.ts` suffix
    
    忽略带有`.test.ts`后缀的文件
 *  executing the file (`server/server.ts`) with `ts-node`
    
    使用`ts-node`执行文件( `server/server.ts` )
 *  waiting for three seconds to restart after a file changes
    
    文件更改后等待三秒钟重新启动

*  nodemon --watch server --ext ts --exec ts-node --ignore '\*.test.ts' --delay 3 server/server.ts
    
    nodemon --watch 服务器 --ext ts --exec ts-node --ignore '\* .test.ts'-- delay 3 server / server.ts

This command combines `--watch`, `--ext`, `--exec`, `--ignore`, and `--delay` options to satisfy the conditions for our scenario.

这个命令把`--watch` ， `--ext` ， `--exec` ， `--ignore` ，并`--delay`选项，以满足我们的方案的条件。

## 第4步-使用配置 **(**Step 4 — Using Configurations**)** ##

In the previous example, adding configuration switches when running `nodemon` can get quite tedious. A better solution for projects that need specific configurations is to specify these configs in a `nodemon.json` file.

在前面的示例中，在运行`nodemon`时添加配置开关可能会非常繁琐。 对于需要特定配置的项目，更好的解决方案是在`nodemon.json`文件中指定这些配置。

For example, here are the same configurations as the previous command line example, but placed in a `nodemon.json` file:

例如，这是与前面的命令行示例相同的配置，但是放置在`nodemon.json`文件中：

nodemon.json

{
      "watch": ["server"],
      "ext": "ts",
      "ignore": ["*.test.ts"],
      "delay": "3",
      "execMap": {
        "ts": "ts-node"
      }
    }

Note the use of `execMap` instead of the `--exec` switch. `execMap` allows you to specify binaries that should be used given certain file extensions.

请注意使用`execMap`而不是`--exec`开关。 `execMap`允许您指定在某些文件扩展`execMap`应使用的二进制文件。

Alternatively, if you’d rather not add a `nodemon.json` config file to your project, you can add these configurations to the `package.json` file under a `nodemonConfig` key:

另外，如果您不想将`nodemon.json`配置文件添加到项目中，则可以在`nodemonConfig`键下将这些配置添加到`package.json`文件中：

package.json

{
      "name": "test-nodemon",
      "version": "1.0.0",
      "description": "",
      "nodemonConfig": {
        "watch": [
          "server"
        ],
        "ext": "ts",
        "ignore": [
          "*.test.ts"
        ],
        "delay": "3",
        "execMap": {
          "ts": "ts-node"
        }
      },
      // ...

Once you make the changes to either `nodemon.json` or `package.json`, you can then start `nodemon` with the desired script:

一旦对`nodemon.json`或`package.json`进行了更改，就可以使用所需的脚本启动`nodemon` ：

*  nodemon server/server.ts
    
    nodemon服务器/server.ts

`nodemon` will pick up the configurations and use them. This way, your configurations can be saved, shared, and repeated to avoid copy-and-pasting or typing errors in the command line.

`nodemon`将选择并使用配置。 这样，可以保存，共享和重复您的配置，以避免在命令行中进行复制粘贴或输入错误。

## 结论 **(**Conclusion**)** ##

In this article, you explored how to use `nodemon` with your Node.js applications. This tool helps automate the process of stopping and starting a Node server to view the changes.

在本文中，您探索了如何在Node.js应用程序中使用`nodemon` 。 该工具有助于自动化停止和启动节点服务器以查看更改的过程。

For more information about the available features and troubleshooting errors, consult [the official documentation][].

有关可用功能和故障排除错误的更多信息，请参阅[官方文档][the official documentation] 。

If you’d like to learn more about Node.js, check out [our Node.js topic page][] for exercises and programming projects.

如果您想了解有关Node.js的更多信息，请查看[我们的Node.js主题页面，][our Node.js topic page]以进行练习和编程项目。

> 翻译自: [https://www.digitalocean.com/community/tutorials/workflow-nodemon][https_www.digitalocean.com_community_tutorials_workflow-nodemon]

node nodemon

[nodemon]: https://nodemon.io/
[rem]: https://twitter.com/rem
[How to Install Node.js and Create a Local Development Environment]: https://www.digitalocean.com/community/tutorial_series/how-to-install-node-js-and-create-a-local-development-environment
[npm or Yarn]: https://www.digitalocean.com/community/tutorials/nodejs-adding-removing-packages-npm-yarn
[dev dependency]: https://docs.npmjs.com/specifying-dependencies-and-devdependencies-in-a-package-json-file
[npm scripts]: https://www.digitalocean.com/community/tutorials/nodejs-utilizing-npm-scripts-during-development
[npx]: https://www.digitalocean.com/community/tutorials/workflow-npx
[Express server setup]: https://www.digitalocean.com/community/tutorials/nodejs-express-basics
[ts-node]: https://github.com/TypeStrong/ts-node
[the official documentation]: https://github.com/remy/nodemon
[our Node.js topic page]: https://www.digitalocean.com/community/tags/node-js
[https_www.digitalocean.com_community_tutorials_workflow-nodemon]: https://www.digitalocean.com/community/tutorials/workflow-nodemon