使用 concurrently 并行地运行多个命令（同时跑前端和后端的服务）

我现在有一个项目是这样的，前端是用 React 写的，后端是用 Nodejs，目录结构如下：

.
├── README.md
├── backend
├── node_modules
├── package.json
├── public
├── src
└── yarn.lock

这个 package.json 的内容如下：

{
  "name": "crudtest",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "classnames": "^2.2.5",
    "concurrently": "^3.5.1",
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "react-redux": "^5.0.7",
    "react-router-dom": "^4.2.2",
    "react-scripts": "1.1.1",
    "redux": "^3.7.2",
    "redux-thunk": "^2.2.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
  },
  "devDependencies": {
    "redux-devtools-extension": "^2.13.2"
  },
  "proxy": "http://localhost:8080"
}

而后端项目是放在 backend 这个目录中，其目录结构如下：

backend
├── etc
├── node_modules
├── package-lock.json
├── package.json
└── server.js

它的 package.json 文件，内容如下：

{
  "name": "backend",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "nodemon --exec babel-node -- ./server.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "body-parser": "^1.18.2",
    "express": "^4.16.2",
    "mongodb": "^3.0.4"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "nodemon": "^1.17.1"
  }
}

现在前端项目要运行起来简单，只要运行如下命令即可。

$ npm run start

就会跑 3000 端口。

那么要运行服务器的程序的话，可能要这样：

$ cd backend
$ npm run start

就会跑 8080 端口。

那么有没有一种方法同时运行两个服务呢？

就是用一条命令跑两个服务。

解决方法如下：

1、在项目根目录下，运行：

$ npm i concurrently --save
或
$ yarn add concurrently

1. 然后更改 package.json 文件，如下：

{
  "name": "crudtest",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "classnames": "^2.2.5",
    "concurrently": "^3.5.1",
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "react-redux": "^5.0.7",
    "react-router-dom": "^4.2.2",
    "react-scripts": "1.1.1",
    "redux": "^3.7.2",
    "redux-thunk": "^2.2.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "server": "npm start --prefix backend",
    "dev": "concurrently \"npm run server\" \"npm run start\""
  },
  "devDependencies": {
    "redux-devtools-extension": "^2.13.2"
  },
  "proxy": "http://localhost:8080"
}

主要添加了下面这两行：

"server": "npm start --prefix backend",
"dev": "concurrently \"npm run server\" \"npm run start\""

有了 --prefix backend 就不用 cd backend 了，也就是说运行 npm run server 就会跑后端的服务，相当于：

$ cd backend
$ npm run start

最后运行 npm run dev 相当于同时运行下面两条命令：

$ npm run server
$ npm run start

界面如下：

完结。

类似的工具：

https://github.com/mysticatea/npm-run-all