npm入手笔记0x003-一些常见问题记录

摘要：如何选择就如果上面所有，需要打包进生产环境就保存到，只是在开发或者打包的时候使用的就保存到即可。提示不能发布当前版本解决方案不能发布已经发布的版本，修改一下版本号就可以了想不到了，想到了再写资源项目

本篇文章承接上文，记录的是一些使用过程中的疑惑

解决方案：使用淘宝cnpm，推荐使用cnpm，因为如果修改npm仓库，将会导致无法发布包。

$ npm install -g cnpm --registry=https://registry.npm.taobao.org
/usr/local/bin/cnpm -> /usr/local/lib/node_modules/cnpm/bin/cnpm
+ cnpm@5.1.1
updated 4 packages in 10.035s

$ cnpm install lodash

解决方案：推荐第一种，简单！

第一种：给全局包安装路径权限

$ npm config get prefix
/usr/local
$ sudo chown -R $(whoami) $(npm config get prefix)/{lib/node_modules,bin,share}

第二种：修改全局包安装路径到有权限的地方

 $ mkdir ~/.npm-global
 $ npm config set prefix "~/.npm-global"
 $ export PATH=~/.npm-global/bin:$PATH
 $ source ~/.profile

本质上是没有差别的，只是一个装在了全局文件夹，一个装在了项目文件夹。全局文件夹中的包到处都可以引用，而装在项目文件夹中的包只有该项目才可以引用（其实都可以引用），以下做实验来演示

新建文件夹0x007-local-global-diff1,0x008-local-global-diff2,0x009-local-global-diff3,0x010-local-global-diff4,并且使用命名空间做包名

$ mkdir 0x007-local-global-diff1
$ mkdir 0x008-local-global-diff2
$ mkdir 0x009-local-global-diff3
$ mkdir 0x010-local-global-diff4

编写并发布@followwinter/0x007-local-global-diff1@1.0.0

$ cd 0x007-local-global-diff1
$ npm init
This utility will walk you through creating a package.json file.
It only covers the most common items, and tries to guess sensible defaults.

See `npm help json` for definitive documentation on these fields
and exactly what they do.

Use `npm install ` afterwards to install a package and
save it as a dependency in the package.json file.

Press ^C at any time to quit.
package name: (0x007-local-global-diff1) @followwinter/0x007-local-global-diff1
version: (1.0.0) 
description: 
entry point: (index.js) 
test command: 
git repository: 
keywords: 
author: 
license: (ISC) 
About to write to /MY_PROJECT/PROJECT_OWN/NodeJS/npm/0x007-local-global-diff1/package.json:

{
  "name": "@followwinter/0x007-local-global-diff1",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo "Error: no test specified" && exit 1"
  },
  "author": "",
  "license": "ISC"
}


Is this ok? (yes) 

$ vim index.js
// index.js
exports.printMsg = function() {
  console.log("This is a message from the @followwinter/0x007-local-global-diff1@1.0.0 package");
}
$ npm publish --access public
+ @followwinter/0x007-local-global-diff1@1.0.0

安装并引用@followwinter/0x007-local-global-diff1@1.0.0

$ cd  0x008-local-global-diff2
$ vim index.js
$ npm install @followwinter/0x007-local-global-diff1
npm WARN saveError ENOENT: no such file or directory, open "/MY_PROJECT/PROJECT_OWN/NodeJS/npm/0x008-local-global-diff2/package.json"
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN enoent ENOENT: no such file or directory, open "/MY_PROJECT/PROJECT_OWN/NodeJS/npm/0x008-local-global-diff2/package.json"
npm WARN 0x008-local-global-diff2 No description
npm WARN 0x008-local-global-diff2 No repository field.
npm WARN 0x008-local-global-diff2 No README data
npm WARN 0x008-local-global-diff2 No license field.

+ @followwinter/0x007-local-global-diff1@1.0.0
added 1 package in 2.361s

$ vim index.js
// index.js
var myModule = require("@followwinter/0x007-local-global-diff1");
console.log(myModule);
myModule.printMsg();

$ node index.js
{ printMsg: [Function] }
This is a message from the @followwinter/0x007-local-global-diff1@1.0.0 package

更新@followwinter/0x007-local-global-diff1@1.0.0版本

$ cd 0x007-local-global-diff1/
$  vim index.js

// index.js
exports.printMsg = function() {
  console.log("This is a message from the @followwinter/0x007-local-global-diff1@1.0.2 package");
}

$ vim package.js
// package.js
{
  "name": "@followwinter/0x007-local-global-diff1",
  "version": "1.0.2",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo "Error: no test specified" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

$ npm publish --access public
+ @followwinter/0x007-local-global-diff1@1.0.2

全局安装新版本并引用

$ cd 0x009-local-global-diff3/
$ npm install @followwinter/0x007-local-global-diff1 -g
+ @followwinter/0x007-local-global-diff1@1.0.2
$ vim index.js
// index.js
var myModule = require("@followwinter/0x007-local-global-diff1");
console.log(myModule);
myModule.printMsg();

$ node index.js
{ printMsg: [Function] }
This is a message from the @followwinter/0x007-local-global-diff1@1.0.2 package

运行0x008-local-global-diff2，验证全局和本地的引用顺序

$ cd 0x008-local-global-diff2
$ node index.js
This is a message from the @followwinter/0x007-local-global-diff1@1.0.0 package

0x010引用0x008中的node_modules中的0x007

$ cd 0x010-local-global-diff4/
$ vim index.js

// index.js
var myModule = require("/MY_PROJECT/PROJECT_OWN/NodeJS/npm/0x008-local-global-diff2/node_modules/@followwinter/0x007-local-global-diff1");
console.log(myModule);
myModule.printMsg();

$ node index.js 
{ printMsg: [Function] }
This is a message from the @followwinter/0x007-local-global-diff1@1.0.0 package

所以包的查找顺序是

- 项目的`node_modules`文件夹
- 全局的`node_modules`文件夹

但是都可以找到就是,主要是查找路径和顺序的问题，而关于如何抉择存在哪呢？考虑的问题有一下几点

是否在意全局文件的占用问题，全局文件不手动删除会一直存在，占用磁盘空间

是否在多个项目使用不同版本？版本之间还有冲突？如果是这样，推荐还是保存在本地

是否有命令行功能？如果有推荐安装在全局，因为安装本地调用需要调整调用路径，很麻烦

区别：没有啥区别，只有语义上的区别，dependencies一般说的是项目运行需要的包，或者说需要打包进生产环境的包，比如jQuery、lodash之类，而dependencies-dev一般说的是开发需要用的包，比如webpack、gulp之类，在生产环境中不需要打包。
如何选择就如果上面所有，需要打包进生产环境就保存到dependencies，只是在开发或者打包的时候使用的就保存到dependencies-dev即可。

npm ERR! publish Failed PUT 403
npm ERR! code E403
npm ERR! You cannot publish over the previously published version 1.0.2. : @followwinter/0x007-local-global-diff1

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/FollowWinter/.npm/_logs/2017-09-10T14_01_59_753Z-debug.log

解决方案：不能发布已经发布的版本，修改一下版本号就可以了

项目github