下雪了，在家闲着，不如写一个npm 包发布。简单的 npm 包的发布网上有很多教程，我就不记录了。这里记录下，一个复杂的 npm 包发布，复杂指的构建环境复杂。

整个工程使用 rollup 来构建，其中会引进 babel 来转译 ES6，利用 Eslint 来规范代码的书写风格，最后代码的发布会经过 terser 压缩。同时发布 umd、es 格式的版本以供外部调用。

完整目录结构如下：

下面是整个过程的记录

一、初始化工程

yarn init -y

初始化后，修改 package.json 内容，如 name(项目名)，description(项目描述)等信息。

二、安装 rollup

yarn add rollup@1.0.0 --dev

三、创建配置文件 rollup.config.js

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  }
}

四、安装 babel

yarn add rollup-plugin-babel@4.2.0 @babel/core@7.2.2 @babel/preset-env@7.2.3 --dev

五、配置 babel

1、创建配置文件 .babelrc

{
  "presets": [
   [
    "@babel/preset-env",
    {
     "modules": false
    }
   ]
  ]
}

2、与 rollup 集成，在 rollup.config.js 中配置 plugins

import babel from 'rollup-plugin-babel'

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  },
  plugins: [
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    })
  ]
}

六、安装 eslint

yarn add eslint@5.11.1

七、配置 eslint

1、生成 eslint 配置

.\node_modules\.bin\eslint --init

2、与 rollup 集成，在 rollup.config.js 中配置 plugins

import babel from 'rollup-plugin-babel'
import { eslint } from 'rollup-plugin-eslint'

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  },
  plugins: [
    eslint({
      include: ['src/**'],
      exclude: ['node_modules/**']
    }),
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    })
  ]
}

八、commonjs 兼容

yarn add rollup-plugin-commonjs@9.2.0 rollup-plugin-node-resolve@4.0.0 --dev

九、与 rollup 集成，在 rollup.config.js 中配置 plugins

import babel from 'rollup-plugin-babel'
import { eslint } from 'rollup-plugin-eslint'
import resolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  },
  plugins: [
    resolve({
      jsnext: true,
      main: true,
      browser: true
    }),
    commonjs(),
    eslint({
      include: ['src/**'],
      exclude: ['node_modules/**']
    }),
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    })
  ]
}

十、安装 terser, 用来压缩代码

yarn add rollup-plugin-terser@4.0.0 --dev

十一、与 rollup 集成，在 rollup.config.js 中配置 plugins

import babel from 'rollup-plugin-babel'
import { eslint } from 'rollup-plugin-eslint'
import resolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'
import { terser } from 'rollup-plugin-terser'

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  },
  plugins: [
    resolve({
      jsnext: true,
      main: true,
      browser: true
    }),
    commonjs(),
    eslint({
      include: ['src/**'],
      exclude: ['node_modules/**']
    }),
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    }),
    terser()
  ]
}

十二、引入环境变量，实践差异化打包

1、安装插件

yarn add rollup-plugin-replace@2.1.0 --dev

2、配置 plugins

import babel from 'rollup-plugin-babel'
import { eslint } from 'rollup-plugin-eslint'
import resolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'
import { terser } from 'rollup-plugin-terser'
import replace from 'rollup-plugin-replace'

export default {
  input: 'src/index.js',
  output: {
    file: 'index.common.js',
    format: 'umd',
    name: 'index'
  },
  plugins: [
    resolve({
      jsnext: true,
      main: true,
      browser: true
    }),
    commonjs(),
    eslint({
      include: ['src/**'],
      exclude: ['node_modules/**']
    }),
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    }),    
    replace({
      exclude: 'node_modules/**',
      ENVIRONMENT: JSON.stringify(process.env.NODE_ENV)
    }),
    terser()
  ]
}

十三、参数化配置，加入版权说明，最终配置如下

import resolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'
import { eslint } from 'rollup-plugin-eslint'
import babel from 'rollup-plugin-babel'
import replace from 'rollup-plugin-replace'
import { terser } from 'rollup-plugin-terser'

const pJson = require('./package.json')

const version = pJson.version
const license = pJson.license

const banner =
  '/*!\n' +
  ` * ${pJson.name} v${version}\n` +
  ` * (c) 2018-${new Date().getFullYear()}\n` +
  ` * Released under the ${license} License.\n` +
  ' */'

const ENV = process.env.NODE_ENV.trim()

const paths = {
  input: {
    root: 'src/index.js'
  },
  output: {
    root: 'dist/'
  }
}

const fileNames = {
  development: 'index.common.js',
  production: 'index.common.js',
  production6: 'index.esm.js'
}
const fileName = fileNames[ENV]

export default {
  input: `${paths.input.root}`,
  output: {
    file: `${paths.output.root}${fileName}`,
    format: ENV === 'production6' ? 'es' : 'umd',
    name: 'index',
    banner
  },
  plugins: [
    resolve({
      jsnext: true,
      main: true,
      browser: true
    }),
    commonjs(),
    eslint({
      include: ['src/**'],
      exclude: ['node_modules/**']
    }),
    babel({
      exclude: 'node_modules/**',
      runtimeHelpers: true
    }),
    replace({
      exclude: 'node_modules/**',
      ENVIRONMENT: JSON.stringify(process.env.NODE_ENV)
    }),
    ENV && ENV.includes('production') && terser({ output: { comments: /^!/ } })
  ]
}

三、业务代码编写

在 src/index.js 中编写具体业务代码

四、打包

在 package.json 中添加

"scripts": {
    "dev": "set NODE_ENV=development && rollup -c",
    "build": "yarn run buildcjs && yarn run buildesm",
    "buildcjs": "set NODE_ENV=production && rollup -c",
    "buildesm": "set NODE_ENV=production6 && rollup -c"
}

运行命令

yarn run build

五、发布

npm publish

发布前记得记得 注册 帐号，记得修改 package.json 中 private 字段为 false

"private": false

后记：rollup-plugin-uglify@6.0.0 在 rollup@1.0.0 时有警告，文章中原 rollup-plugin-uglify 被替换成 rollup-plugin-terser