nodejs使用模块

创建和加载模块

nodejs提供了exports和require来对模块进行操作，exports是模块公开的接口，require用于获取模块的exports对象

创建一个module.js文件，并公开一个方法

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exports.sayHello = function(name){
    console.log('Hello '+name);
}

在同目录下创建usemodule.js文件，调用上述方法

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// 加载module模块
var myModule = require('./module');
myModule.sayHello('老张');

执行结果

1 2	zhanghedeMacBook:module zhanghe$ node usemodule.js Hello 老张

在开发nodejs程序的时候需要使用很多模块，总不能一个一个的安装吧？那当然不会这么干，npm允许使用package.json文件来指定应用程序中要用的模块

{
  "name": "exam", // 包的名称
  "version": "1.0.0",//版本
  "private": true,
  "scripts": {
    "serve": "vue-cli-service serve --mode dev",
    "build": "vue-cli-service build --mode prod",
    "build:dev": "vue-cli-service build --mode dev",
    "build:test": "vue-cli-service build --mode test",
    "build:pre": "vue-cli-service build --mode pre",
    "build:prod": "vue-cli-service build --mode prod",
    "lint": "vue-cli-service lint"
  },
  "dependencies": { // 包的依赖
    "axios": "^0.19.0",
    "core-js": "^3.10.0",
    "element-ui": "^2.15.0",
    "js-cookie": "2.2.0",
    "normalize.css": "8.0.1",
    "nprogress": "0.2.0",
    "vue": "^2.6.10",
    "vue-router": "^3.5.1",
    "vuex": "^3.6.2"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "^4.5.12",
    "@vue/cli-plugin-eslint": "^4.5.12",
    "@vue/cli-plugin-router": "^4.5.12",
    "@vue/cli-plugin-vuex": "^4.5.12",
    "@vue/cli-service": "^4.5.12",
    "@vue/eslint-config-standard": "^4.0.0",
    "babel-eslint": "^10.0.3",
    "eslint": "^5.16.0",
    "eslint-plugin-vue": "^5.0.0",
    "node-sass": "^4.14.1",
    "sass-loader": "^8.0.0",
    "svg-sprite-loader": "4.1.6",
    "vue-template-compiler": "^2.6.10"
  }
}