npm入手筆記0x003-一些常見問題記錄

0x001 概述

本篇文章承接上文，記錄的是一些使用過程當中的疑惑

0x001 牆的緣由使得包下載太慢

解決方案：使用淘寶cnpm，推薦使用cnpm，由於若是修改npm倉庫，將會致使沒法發佈包。

$ 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

0x002 沒法安裝全局包，提示EACCES ，沒有權限

解決方案：推薦第一種，簡單！

• 第一種：給全局包安裝路徑權限

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

• 第二種：修改全局包安裝路徑到有權限的地方

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

0x003 全局包和本地包的區別以及如何抉擇

本質上是沒有差異的，只是一個裝在了全局文件夾，一個裝在了項目文件夾。全局文件夾中的包處處均可以引用，而裝在項目文件夾中的包只有該項目才能夠引用（其實均可以引用），如下作實驗來演示

• 新建文件夾0x007-local-global-diff1,0x008-local-global-diff2,0x009-local-global-diff3,0x010-local-global-diff4,而且使用命名空間作包名

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

• 編寫併發布@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 <pkg>` 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

1. 安裝並引用@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

• 全局安裝新版本並引用

$ 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

• 運行0x008-local-global-diff2，驗證全局和本地的引用順序

$ 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

因此包的查找順序是

- 項目的`node_modules`文件夾
- 全局的`node_modules`文件夾

可是均可以找到就是,主要是查找路徑和順序的問題，而關於如何抉擇存在哪呢？考慮的問題有一下幾點

• 是否在乎全局文件的佔用問題，全局文件不手動刪除會一直存在，佔用磁盤空間

• 是否在多個項目使用不一樣版本？版本之間還有衝突？若是是這樣，推薦仍是保存在本地

• 是否有命令行功能？若是有推薦安裝在全局，由於安裝本地調用須要調整調用路徑，很麻煩

0x004 dependencies和dependencies-dev節點的區別以及如何抉擇

區別：沒有啥區別，只有語義上的區別，dependencies通常說的是項目運行須要的包，或者說須要打包進生產環境的包，好比jQuery、lodash之類，而dependencies-dev通常說的是開發須要用的包，好比webpack、gulp之類，在生產環境中不須要打包。
如何選擇就若是上面全部，須要打包進生產環境就保存到dependencies，只是在開發或者打包的時候使用的就保存到dependencies-dev便可。

0x005 提示不能發佈當前版本

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

解決方案：不能發佈已經發布的版本，修改一下版本號就能夠了

0x006 想不到了，想到了再寫

0x007 資源

• 項目github