npm包管理npm其实是Node.js的包管理工具（node package manager）。为啥我们需要一个包管理工具呢？因为我们在Node.js上开发时，会用到很多别人写的JavaScript代码。如果我们要使用别人写的某个包，每次都根据名称搜索一下官方网站，下载代码，解压，再使用，非常繁琐。于是一个集中管理的工具应运而生：大家都把自己开发的模块打包后放到npm官网上，如果要使用，直接通过npm安装就可以直接用，不用管代码存在哪，应该从哪下载。更重要的是，如果我们要使用模块A，而模块A又依赖于模块B，模块B又依赖于模块C和模块D，npm可以根据依赖关系，把所有依赖的包都下载下来并管理起来。否则，靠我们自己手动管理，肯定既麻烦又容易出错。npm的基础使用npm的指令其实常用的并不多官方文档；列出来如下面：access Set access level on published packagesadduserAdd a registry user accountauditRun a security auditbinDisplay npm bin folderbugs Bugs for a package in a web browser maybebuildBuild a packagebundleREMOVED 已删除cacheManipulates packages cacheciInstall a project with a clean slatecompletion Tab Completion for npmconfigManage the npm configuration filesdedupeReduce duplicationdeprecateDeprecate a version of a packagedist-tagModify package distribution tagsdocsDocs for a package in a web browser maybedoctorCheck your environmentseditEdit an installed packageexploreBrowse an installed packagehelp-searchSearch npm help documentationhelpGet help on npmhookManage registry hooksinitcreate a package.json fileinstall-ci-testInstall a project with a clean slate and run testsinstall-testInstall package(s) and run testsinstallInstall a packagelinkSymlink a package folderlogout Log out of the registrylsList installed packagesnpm javascript package manageroutdatedCheck for outdated packagesowner Manage package ownerspackCreate a tarball from a packagepingPing npm registryprefixDisplay prefixprofileChange settings on your registry profilepruneRemove extraneous packagespublish Publish a packagerebuildRebuild a packagerepo Open package repository page in the browserrestartRestart a packageroot Display npm rootrun-scriptRun arbitrary package scriptssearch Search for packagesshrinkwrapLock down dependency versions for publicationstarMark your favorite packagesstarsView packages marked as favoritesstartStart a packagestopStop a packageteamManage organization teams and team membershipstestTest a packagetokenManage your authentication tokensuninstallRemove a packageunpublishRemove a package from the registryupdateUpdate a packageversion Bump a package versionviewView registry infowhoamiDisplay npm usernameinit初始化创建package.jsonnpm init [–force|-f|–yes|-y|–scope]npm init <@scope> (same as npx <@scope>/create)npm init [<@scope>/]<name> (same as npx [<@scope>/]create-<name>)search搜索查看远程npm相关资源包信息npm search [-l|–long] [–json] [–parseable] [–no-description] [search terms …]aliases: s, se, findinstall可以是说是install是最为常见的命令官方介绍，npm install (with no args, in package dir)npm install [<@scope>/]<name>npm install [<@scope>/]<name>@<tag>npm install [<@scope>/]<name>@<version>npm install [<@scope>/]<name>@<version range>npm install <git-host>:<git-user>/<repo-name>npm install <git repo url>npm install <tarball file>npm install <tarball url>npm install <folder> alias: npm icommon options: [-P|–save-prod|-D|–save-dev|-O|–save-optional] [-E|–save-exact] [-B|–save-bundle] [–no-save] [–dry-run] In global mode (ie, with -g or –global appended to the command), it installs the current package context (ie, the current working directory) as a global package. The -g or –global argument will cause npm to install the package globally rather than locally. The -f or –force argument will force npm to fetch remote resources even if a local copy exists on disk.上面的还介绍已经很详细了，所以这里只是讲一下npm install packageName [|–save |–save-prod|–save-dev]的区别；npm install babel npm5以前,会把X包安装到node_modules目录中，不会修改package.json的dependencies字段，之后运行npm install命令时，不会自动安装Xnpm install babelnpm5以后,会把X包安装到node_modules目录中，会修改package.json的dependencies字段，之后运行npm install命令时，会自动安装X, 线上环境时会被安装npm install babel -P -P, –save-prod: Package will appear in your dependencies. This is the default unless -D or -O are present. Package will appear in your dependencies, With the –production flag (or when the NODE_ENV environment variable is set to production), npm will install modules listed in dependencies.npm install babel -DPackage will appear in your devDependencies，With the –production flag (or when the NODE_ENV environment variable is set to production), npm will not install modules listed in devDependencies. 会把X包安装到node_modules目录中，会在package.json的devDependencies属性下添加X，之后运行npm install命令时，会自动安装X到node_modules目录中，之后运行npm install –production或者注明NODE_ENV变量值为production时，不会自动安装X到node_modules目录中update升级某个资源包或者全部资源包到某一个版本或者匹配的最新版本。npm update [-g] [<pkg>…]aliases: up, upgradeuninstall移除某个资源包npm uninstall [<@scope>/]<pkg>[@<version>]… [-S|–save|-D|–save-dev|-O|–save-optional|–no-save]aliases: remove, rm, r, un, unlinknpm包创建、编写、测试、维护Node出现之前，JavaScript是缺少包结构的。CommonJS致力于改变这种现状，于是定义了包的结构规范。而NPM的出现则是为了在CommonJS规范的基础上，实现解决包的安装卸载，依赖管理，版本管理等问题。require的查找机制明了之后，我们来看一下包的细节。一个符合CommonJS规范的包应该是如下这种结构：一个package.json文件应该存在于包顶级目录下二进制文件应该包含在bin目录下(可选)JavaScript代码入库是index.js，其他包含在lib目录下文档应该在doc目录下(可选)单元测试应该在test目录下(可选)初始化包创建包的根目录mkdir testpackage初始化npm init // 需要进行一些基本配置编写创建入口文件touch index.js编写代码const updateQueryString = function(url, key, value) { let urlParts = url.split(’#’), hash = ‘’, uri = urlParts.shift(), re = new RegExp(([?&])${key}=.*?(&|$), ‘i’), separator = uri.indexOf(’?’) !== -1 ? ‘&’ : ‘?’, encodeKey = encodeURIComponent(key), encodeValue = encodeURIComponent(value); urlParts.length > 0 && (hash = #${urlParts.join('#')}); if (uri.match(re)) { return uri.replace(re, $1${encodeKey}=${encodeValue}$2) + hash; } else { return ${uri}${separator}${encodeKey}=${encodeValue}${hash}; }};// 最后的导出部分module.exports = { updateQueryString};测试创建包的根目录npm i mocha -D // 安装测试库npm i chai -D // 安装断言库mkdir testcd testtouch index.test.js编写测试代码const utils = require(’./../index.js’);const expect = require(‘chai’).expect;let { updateQueryString} = utils;describe(‘updateQueryString函数的测试’, function() { it(‘https://test.com/path?test=11 修改test参数为22 应该等于 https://test.com/path?test=22', function() { expect(updateQueryString(‘https://test.com/path?test=11', ’test’, 22)).to.be.equal(‘https://test.com/path?test=22'); });});运行测试cd …/node_modules/mocha/bin/mocha npm包的发布注册账号npm官网终端执行 npm login,输入用户名和密码 、邮箱npm publish 发布Organization包我们经常可以看到@angular、@ionic他们的包， 都可以以@开头，那么我们的可不可以，原来angular、ionic都属于一个组织（Organization）只有新创建一个Organization组织之后，才能创建@testorg/testpackname这样的包！！！那么我们就可以去官网上创建我们的Organization，命名之后，官方步骤，初始化npm init –scope=<your_org_name>npm init foo -> npx create-foonpm init @usr/foo -> npx @usr/create-foonpm init @usr -> npx @usr/create修改package.json里面的name字段为@your_org_name/<pkg_name>发布npm publish –access public // 公开包发布npm包支持esmodule