# 使用NPM

## 使用NPM

* 先安裝Node.js
* 以下為基本指令

### npm install

npm install -g (使用後可在cmd的任何路徑輸入package名稱執行，但如果是想在js檔內直接使用require的話，要再把環境變數加上才行)(如此即可不用在每個專案資料夾個別安裝package))\
(記得名稱要是NODE\_PATH)

**所以共有兩個環境變數:**

1. 一個是NODE\_PATH => 安裝全域包後給js檔案require用

> NODE\_PATH `C:\Program Files\nodejs\node_modules`
>
> Mac 使用 require global package 可用\
> export NODE\_PATH=/usr/local/lib/node\_modules
>
> 如果不知道路徑是什麼可以先試著安裝-g 模組 然後看一下他print出來的安裝路徑

2.另一個是`C:\Users\Jason\AppData\Roaming\npm`給在cmd直接輸入module名稱用

> PATH `C:\Users\Jason\AppData\Roaming\npm`
>
> 預設 安裝Node.js會自動幫你加上

```
npm install --save
npm uninstall
npm search
npm ls -g
npm ls -gl
npm ls -l
npm update -g
npm update
```

### NPM CI

npm version 6 後的功能，通常會在 ci 流程中使用，跟 npm install 相似，但具有 dependency version 依賴檢查功能，安裝套件的同時不會自動幫你更新套件版本，提供更穩定的特性 。

```
npm ci
```

1. **Dependency Resolution**: It installs the exact versions of dependencies as specified in the `package-lock.json` or `npm-shrinkwrap.json` file, ignoring the `package.json` if there are any differences. This ensures that every install results in the exact same file structure in `node_modules` across all machines.
2. **Speed**: It can be faster than `npm install` because it skips certain user-oriented features. It is more efficient as it bypasses the package version resolution step since the exact dependency tree is already defined.
3. **Clean Slate**: Before installing the new dependencies, `npm ci` will delete the existing `node_modules` folder, ensuring that there are no leftover artifacts from previous installations.
4. **Strictness**: If there are discrepancies between the `package-lock.json` and the `package.json`, `npm ci` will throw an error and stop the installation process. This strictness ensures that the `package-lock.json` is up to date and has not been tampered with.
5. **Non-Interactive**: It does not write to the `package.json` or `package-lock.json` files; any updates to dependencies must be done explicitly by the developer.

<https://docs.npmjs.com/cli/v8/commands/npm-ci>

### 為了避免部屬後環境module過大，可不必安裝dev用的module

一開始開發時將套件安裝到devDependencies

```
npm install --save-dev  //記得save跟dev要用-連再一起
```

部屬時安裝

```
npm install --production
```

> 當npm install出現一些版本錯誤，而無法安裝，這是記得先更新本地端`npm install -g`(更新global的package)\
> 更多可參考\
> <https://docs.npmjs.com/>

## package.json教學

1. `"main"`表示require('模組名稱')所預設加載的文件。

2.如下的寫法可用`npm run start`輸入此即會執行`node index.js`

```
"scripts": {
  "start": "node index.js"
},
```

1. config用來設定環境變量，如下

```
"config": { "port" : "8080" }
```

可在程式中使用\
`process.env.npm_package_config_port`讀取到

比較常用設定環境變量的方法為

```
console.log(process.env.PORT)
```

然後執行

```
PORT=8000 node test1.js //mac
```

> windows如果不行可以使用git bash來執行

nodemon可用類似如下

```
set PORT=8080 && nodemon test.js
```

\# 控制版本

使用shrinkwrap

<http://syshen.cc/post/18425250521/npm-shrinkwrap-解決-nodejs-套件複雜的關連性問題>

## 更新npm

```
npm install npm@latest -g
```

## 發佈npm package

```
npm adduser
npm publish
```

> 記得輸入npm publish時要在package.json的同層目錄下
>
> 每次更新記得要更改package.json的版本號

## 發佈為npm global package

> 可以直接在Terminal輸入指令的package

和之前一樣先npm adduser

然後確認package名字沒重複

1.記得將index.js檔案加上

```javascript
#!/usr/bin/env node

.....
```

2.之後因為是global所以加入bin的欄位到package.json檔案裏面

```
  "bin": {
    "gendoc": "./index.js"
  },
```

之後別人使用-g安裝即可使用`gendoc` 指令

> npm link 也可在發布前直接把他加到Local環境變數進行測試，但在windows會沒作用

### 範例：

robot.js

```javascript
#!/usr/bin/env node

const robot = require("robotjs");

// Speed up the mouse.
robot.setMouseDelay(2);


while (true) {
    var twoPI = Math.PI * 2.0;
    var screenSize = robot.getScreenSize();
    var height = (screenSize.height / 2) - 10;
    var width = screenSize.width;

    for (var x = 0; x < width; x++) {
        y = height * Math.sin((twoPI * x) / width) + height;
        robot.moveMouse(x, y);
    }
}
```

package.json

```json
{
  "name": "custom-toolkit",
  "version": "1.0.0",
  "description": "An awesome custom global module",
  "main": "./lib/index.js",
  "scripts": {
      "test": "echo \"Error: no test specified\" && exit 1"
  },
  "bin": {
    "s": "./robot.js"
  },
  "dependencies": {
    "robotjs": "^0.6.0"
  },
  "preferGlobal": true,
  "author": "Eason",
  "license": "MIT"
}
```

之後 `npm install -g ~/資料夾名稱` 即可直接在 terminal 輸入 s ，會執行 robot.js 內容。

## 更新或復原npm版本

(把數字改為你要的版本即可)

```
npm install npm@4.6.1
```

## 切換版本

**n**

```
n use <version>
```

**nvm**

(windows可能無法使用n,所以可以用nvm安裝檔)

下載點:<https://github.com/coreybutler/nvm-windows/releases>

然後

```
nvm install <version>
nvm use <version>
```

## 查看套件以前發布過的版本

```
npm view <套件名稱>
```

## GitHub registry

可以發布 npm 包到 github host 的 registry，相較於預設的 npm registry 差別在於可以直接從 github 發布套件，並且集成 github action。

<https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-npm-registry#installing-a-package>

![](/files/iXG5vwpKQhT2w10Ekzry)

安裝套件前要先登入：

> password 記得使用 github 創建的 personal access token

```
npm login --registry=https://npm.pkg.github.com
```

## 常見問題

**1.node-gyp error**

有時如果安裝的套件是使用C++然後用node-gyp編譯的話，需要預先安裝如下

```
npm install -g node-gyp
```

> 如果是ubuntu還需要安裝build-essential
>
> ```
> sudo apt-get install build-essential
> ```


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