全局安装和本地安装

开发web项目你一定会使用npm包管理器安装各种包，那么你知道Npm包的安装方式：全局安装和本地安装的区别吗？注意：以下示例是window系统

全局安装

全局安装会将安装包放在 C:\Users\[username]\AppData\Roaming\npm\node_modules目录中，可以直接在命令行里使用。

npm install -g packageName

PS C:\Users\wangy\Desktop> npm install -g serve
npm WARN registry Unexpected warning for https://registry.npmjs.org/: Miscellaneous Warning ECONNRESET: request to https://registry.npmjs.org/ajv failed, reason: read ECONNRESET
npm WARN registry Using stale data from https://registry.npmjs.org/ due to a request error during revalidation.
C:\Users\wangy\AppData\Roaming\npm\serve -> C:\Users\wangy\AppData\Roaming\npm\node_modules\serve\bin\serve.js
+ serve@12.0.0
added 88 packages from 42 contributors in 125.131s
PS C:\Users\wangy\Desktop> serve -v
12.0.0

本地安装

将安装包放在 ./node_modules 下，可以通过 require() 来引入本地安装的包。

npm install packageName

const express = require('express');