npm init -y

const puppeteer = require("puppeteer");

const task = async () => {
  // 打开chrome浏览器
  const browser = await puppeteer.launch({
    // 关闭无头模式,方便查看
    headless: false
  });
  // 新建页面
  const page = await browser.newPage();
  // 跳转到掘金
  await page.goto("https://juejin.im");
  // 截屏保存
  await page.screenshot({
    path: "./juejin.png"
  });
};
task();

const puppeteer = require("puppeteer");

const task = async () => {
  // 打开chrome浏览器
  const browser = await puppeteer.launch({
    headless: false
  });
  // 新建页面
  const page = await browser.newPage();
  // 跳转到掘金
  await page.goto("https://juejin.im");
  // 菜单导航对应的类名
  const navSelector = ".view-nav .nav-item";
  // 前端菜单
  const navType = "前端";
  // 等待菜单加载完成...
  await page.waitFor(navSelector);
  // 菜单导航名称
  const navList = await page.$$eval(navSelector, ele =>
    ele.map(el => el.innerText)
  ); // [ '推荐', '后端', '前端', 'Android', 'iOS', '人工智能', '开发工具', '代码人生', '阅读' ]
  // 找出菜单中前端模块对应的索引
  const webNavIndex = navList.findIndex(item => item === navType);
  // 点击前端模块并等待页面跳转完成
  await Promise.all([
    page.waitForNavigation(),
    page.click(`${navSelector}:nth-child(${webNavIndex + 1})`)
  ]);
  // 截屏保存
  await page.screenshot({
    path: "./juejin-web.png"
  });
};
task();

const puppeteer = require("puppeteer");

const task = async () => {
  // 打开chrome浏览器
  const browser = await puppeteer.launch({
    headless: false
  });
  // 新建页面
  const page = await browser.newPage();
  // 跳转到掘金
  await page.goto("https://juejin.im");
  // 菜单导航选择器
  const navSelector = ".view-nav .nav-item";
  // 文章列表选择器
  const listSelector = ".entry-list .item a.title";
  // 菜单类别
  const navType = "前端";
  await page.waitFor(navSelector);
  // 导航列表
  const navList = await page.$$eval(navSelector, ele =>
    ele.map(el => el.innerText)
  );
  // 前端导航索引
  const webNavIndex = navList.findIndex(item => item === navType);
  await Promise.all([
    page.waitForNavigation(),
    page.click(`${navSelector}:nth-child(${webNavIndex + 1})`)
  ]);
  // 等待文章列表选择器加载完成
  await page.waitForSelector(listSelector, {
    timeout: 5000
  });
  // 通过选择器找到对应列表项的标题和链接
  const res = await page.$$eval(listSelector, ele =>
    ele.map(el => ({
      url: el.href,
      text: el.innerText
    }))
  );
  // [ { url: 'https://juejin.im/post/5dd55512f265da47a807cc06',
  //   text: 'if 我是前端Leader，怎么走出小微前端团队的围墙?' },
  // { url: 'https://juejin.im/post/5dd49a45e51d45400206a655',
  //   text: 'Koa还是那个Koa，但是Nodejs已经不再是那个Nodejs' },
  // { url: 'https://juejin.im/post/5dd4b991e51d450818244c30',
  //   text: 'WebSocket 原理浅析与实现简单聊天' },...
};
task();

// resource/index.json
{
  "data": []
}

// tools/index.js
const fs = require("fs");
const fileServer = {
  // 写文件
  write(path, text) {
    fs.writeFileSync(path, text);
  },
  // 读文件
  read(path) {
    return fs.readFileSync(path);
  }
};

const { fileServer } = require("./tools");
const path = require("path");
const task = () => {
  // 获取资讯任务
  const getMsgTask = Promise.all(tasks());
  getMsgTask.then(res => {
    // 读取json
    const { data } = JSON.parse(
      fileServer.read(path.join(resourcePath, "./index.json")).toString()
    );
    // ... 此处省略对资讯 格式化内容
    const text = msgHandle(res);
    // 写入资讯
    fileServer.write(
      path.join(resourcePath, "./index.json"),
      JSON.stringify({
        data: [
          {
            date: now,
            text
          },
          ...data
        ]
      })
    );
  });
};

// 每日18时定时任务
function crontab() {
  schedule.scheduleJob(`00 00 18 * * *`, mainTask);
}
// 任务
function mainTask(){...}

npm install gh-pages --save

  "scripts": {
    "deploy": "gh-pages -d html"
  }

  npm run deploy 将前端资源推送到github上,然后通过 xxx.github.io/xxx  就可以访问了

clientWidth、clientHeight、clientTop、clientLeft

offsetWidth、offsetHeight、offsetTop、offsetLeft

scrollWidth、scrollHeight、scrollTop、scrollLeft

scrollIntoView()、scrollIntoViewIfNeeded()

getComputedStyle()

getBoundingClientRect()

scrollTo()

clientWidth、clientHeight、clientTop、clientLeft


offsetWidth、offsetHeight、offsetTop、offsetLeft


scrollWidth、scrollHeight、scrollTop、scrollLeft


width、height


getComputedStyle()


getBoundingClientRect()

window.onhashchange = function(){
    
    // hash 值改变 
    
    // do you want
}

window.onpopstate = function(){
    // 历史栈 信息改变
    // do you want
}

history.pushState(data[,title][,url]);//向历史记录中追加一条记录

history.replaceState(data[,title][,url]);//替换当前页在历史记录中的信息。

// data: 一个JavaScript对象，与用pushState()方法创建的新历史记录条目关联。无论何时用户导航到新创建的状态，popstate事件都会被触发，并且事件对象的state属性都包含历史记录条目的状态对象的拷贝。

//title: FireFox浏览器目前会忽略该参数，虽然以后可能会用上。考虑到未来可能会对该方法进行修改，传一个空字符串会比较安全。或者，你也可以传入一个简短的标题，标明将要进入的状态。

//url: 新的历史记录条目的地址。浏览器不会在调用pushState()方法后加载该地址，但之后，可能会试图加载，例如用户重启浏览器。新的URL不一定是绝对路径；如果是相对路径，它将以当前URL为基准；传入的URL与当前URL应该是同源的，否则，pushState()会抛出异常。该参数是可选的；不指定的话则为文档当前URL。

{
  "name": "web_router",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "dev": "webpack-dev-server --config ./webpack.config.js"
  },
  "author": "webfansplz",
  "license": "MIT",
  "devDependencies": {
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.28.1",
    "webpack-cli": "^3.2.1",
    "webpack-dev-server": "^3.1.14"
  }
}

'use strict';

const path = require('path');

const webpack = require('webpack');

const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  mode: 'development',
  entry: './src/index.js',
  output: {
    filename: '[name].js'
  },
  devServer: {
    clientLogLevel: 'warning',
    hot: true,
    inline: true,
    open: true,
    //在开发单页应用时非常有用，它依赖于HTML5 history API，如果设置为true，所有的跳转将指向index.html (解决histroy mode 404)
    historyApiFallback: true,
    host: 'localhost',
    port: '6789',
    compress: true
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin(),
    new HtmlWebpackPlugin({
      filename: 'index.html',
      template: 'index.html',
      inject: true
    })
  ]
};

const MODE='';

const ROUTELIST=[];

class WebRouter {
  constructor() {
    
  }
  push(path) {
  
   ...
  }
  replace(path) {
  
   ...
    
  }
  go(num) {
  
   ...
    
  }
}

new WebRouter({
  mode: MODE,
  routeList: ROUTELIST
});

export const ROUTELIST = [
  {
    path: '/',
    name: 'index',
    component: 'This is index page'
  },
  {
    path: '/hash',
    name: 'hash',
    component: 'This is hash page'
  },
  {
    path: '/history',
    name: 'history',
    component: 'This is history page'
  },
  {
    path: '*',
    name: 'notFound',
    component: '404 NOT FOUND'
  }
];

export class HashRouter{
    
}

export class HistoryRouter{
    
}

import { HashRouter } from './hash';
import { HistoryRouter } from './history';
import { ROUTELIST } from './routeList';
//路由模式
const MODE = 'hash';  

class WebRouter {
  constructor({ mode = 'hash', routeList }) {
    this.router = mode === 'hash' ? new HashRouter(routeList) : new HistoryRouter(routeList);
  }
  push(path) {
    this.router.push(path);
  }
  replace(path) {
    this.router.replace(path);
  }
  go(num) {
    this.router.go(num);
  }
}

const webRouter = new WebRouter({
  mode: MODE,
  routeList: ROUTELIST
});

const ELEMENT = document.querySelector('#page');

export class BaseRouter {
 //list = 路由列表
  constructor(list) {
    this.list = list;
  }
  render(state) {
   //匹配当前的路由,匹配不到则使用404配置内容 并渲染~
    let ele = this.list.find(ele => ele.path === state);
    ele = ele ? ele : this.list.find(ele => ele.path === '*');
    ELEMENT.innerText = ele.component;
  }
}

import { BaseRouter } from './base.js'; 

export class HashRouter extends BaseRouter {
  constructor(list) {
    super(list);
    this.handler();
    //监听hash变化事件,hash变化重新渲染  
    window.addEventListener('hashchange', e => {
      this.handler();
    });
  }
  //渲染
  handler() {
    this.render(this.getState());
  }
  //获取当前hash
  getState() {
    const hash = window.location.hash;
    return hash ? hash.slice(1) : '/';
  }
  //获取完整url
  getUrl(path) {
    const href = window.location.href;
    const i = href.indexOf('#');
    const base = i >= 0 ? href.slice(0, i) : href;
    return `${base}#${path}`;
  }
  //改变hash值 实现压入 功能
  push(path) {
    window.location.hash = path;
  }
  //使用location.replace实现替换 功能 
  replace(path) {
    window.location.replace(this.getUrl(path));
  }
  //这里使用history模式的go方法进行模拟 前进/后退 功能
  go(n) {
    window.history.go(n);
  }
}

import { BaseRouter } from './base.js';

export class HistoryRouter extends BaseRouter {
  constructor(list) {
    super(list);
    this.handler();
    //监听历史栈信息变化,变化时重新渲染
    window.addEventListener('popstate', e => {
      this.handler();
    });
  }
  //渲染
  handler() {
    this.render(this.getState());
  }
  //获取路由路径
  getState() {
    const path = window.location.pathname;
    return path ? path : '/';
  }
  //使用pushState方法实现压入功能
  //PushState不会触发popstate事件,所以需要手动调用渲染函数
  push(path) {
    history.pushState(null, null, path);
    this.handler();
  }
  //使用replaceState实现替换功能  
  //replaceState不会触发popstate事件,所以需要手动调用渲染函数
  replace(path) {
    history.replaceState(null, null, path);
    this.handler();
  }
  go(n) {
    window.history.go(n);
  }
}

/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var w = d * 7;
var y = d * 365.25; // why ? 见以下解析第1点

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} [options]
 * @throws {Error} throw an error if val is not a non-empty string or a number
 * @return {String|Number}
 * @api public
 */

module.exports = function (val, options) {
  options = options || {};
  var type = typeof val;
  // 字符串类型且不等于'',走parse方法
  if (type === "string" && val.length > 0) {
    return parse(val);
  }
  // number类型 且 为一个有限数值
  else if (type === "number" && isFinite(val)) {
    // long选项? fmtLong: fmtShort
    return options.long ? fmtLong(val) : fmtShort(val);
  }
  // 类型错误报错
  throw new Error(
    "val is not a non-empty string or a valid number. val=" +
      JSON.stringify(val)
  );
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

// 字符串解析成数字
function parse(str) {
  str = String(str);
  // why? why 100? 见以下解析2,3点
  if (str.length > 100) {
    return;
  }
  // 基操正则..
  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
    str
  );
  if (!match) {
    return;
  }
  var n = parseFloat(match[1]);
  var type = (match[2] || "ms").toLowerCase();
  switch (type) {
    case "years":
    case "year":
    case "yrs":
    case "yr":
    case "y":
      return n * y;
    case "weeks":
    case "week":
    case "w":
      return n * w;
    case "days":
    case "day":
    case "d":
      return n * d;
    case "hours":
    case "hour":
    case "hrs":
    case "hr":
    case "h":
      return n * h;
    case "minutes":
    case "minute":
    case "mins":
    case "min":
    case "m":
      return n * m;
    case "seconds":
    case "second":
    case "secs":
    case "sec":
    case "s":
      return n * s;
    case "milliseconds":
    case "millisecond":
    case "msecs":
    case "msec":
    case "ms":
      return n;
    default:
      return undefined;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */
// 直接相除四舍五入取整
function fmtShort(ms) {
  var msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return Math.round(ms / d) + "d";
  }
  if (msAbs >= h) {
    return Math.round(ms / h) + "h";
  }
  if (msAbs >= m) {
    return Math.round(ms / m) + "m";
  }
  if (msAbs >= s) {
    return Math.round(ms / s) + "s";
  }
  return ms + "ms";
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */
// long选项其实就是单位描述更加详细完整
function fmtLong(ms) {
  var msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return plural(ms, msAbs, d, "day");
  }
  if (msAbs >= h) {
    return plural(ms, msAbs, h, "hour");
  }
  if (msAbs >= m) {
    return plural(ms, msAbs, m, "minute");
  }
  if (msAbs >= s) {
    return plural(ms, msAbs, s, "second");
  }
  return ms + " ms";
}

/**
 * Pluralization helper.
 */

// 复数判断
function plural(ms, msAbs, n, name) {
  // 复数判断,因为Math.round是四舍五入取整,所以此处判断使用n*1.5
  var isPlural = msAbs >= n * 1.5;
  // ms(89999, { long: true }) 1 minute
  // ms(90000, { long: true }) 2 minutes
  return Math.round(ms / n) + " " + name + (isPlural ? "s" : "");
}

// circle.js
const PI = Math.PI

exports.area = r => PI * r * r

exports.circumference = r => 2 * PI * r

// index.js
const circle = require('./circle.js')

console.log(`半径为 4 的圆面积为 ${circle.area(4)}`) // 半径为 4 的圆面积为 50.26548245743669

// square.js

module.exports = width => {
  return {
    area: () => width * width
  }
}

// index.js

const square = require('./square.js')
const mySquare = square(2)
console.log(`The area of my square is ${mySquare.area()}`) // The area of my square is 4

require.main === module

console.log(require.main.filename === __filename) // true

console.log(require.resolve('./square.js')) // /Users/null/meet-nodejs/module/square.js

require(X) from module at path Y
1. If X is a core module,
   a. return the core module
   b. STOP
2. If X begins with './' or '/' or '../'
   a. LOAD_AS_FILE(Y + X)
   b. LOAD_AS_DIRECTORY(Y + X)
3. LOAD_NODE_MODULES(X, dirname(Y))
4. THROW "not found"

LOAD_AS_FILE(X)
1. If X is a file, load X as JavaScript text.  STOP
2. If X.js is a file, load X.js as JavaScript text.  STOP
3. If X.json is a file, parse X.json to a JavaScript Object.  STOP
4. If X.node is a file, load X.node as binary addon.  STOP

LOAD_AS_DIRECTORY(X)
1. If X/package.json is a file,
   a. Parse X/package.json, and look for "main" field.
   b. let M = X + (json main field)
   c. LOAD_AS_FILE(M)
2. If X/index.js is a file, load X/index.js as JavaScript text.  STOP
3. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP
4. If X/index.node is a file, load X/index.node as binary addon.  STOP

LOAD_NODE_MODULES(X, START)
1. let DIRS=NODE_MODULES_PATHS(START)
2. for each DIR in DIRS:
   a. LOAD_AS_FILE(DIR/X)
   b. LOAD_AS_DIRECTORY(DIR/X)

NODE_MODULES_PATHS(START)
1. let PARTS = path split(START)
2. let I = count of PARTS - 1
3. let DIRS = []
4. while I >= 0,
   a. if PARTS[I] = "node_modules" CONTINUE
   c. DIR = path join(PARTS[0 .. I] + "node_modules")
   b. DIRS = DIRS + DIR
   c. let I = I - 1
5. return DIRS

// a.js
console.log('a starting')
exports.done = false
const b = require('./b.js')
console.log('in a, b.done = %j', b.done)
exports.done = true
console.log('a done')

// b.js
console.log('b starting')
exports.done = false
const a = require('./a.js')
console.log('in b, a.done = %j', a.done)
exports.done = true
console.log('b done')

// main.js
console.log('main starting')
const a = require('./a.js')
const b = require('./b.js')
console.log('in main, a.done=%j, b.done=%j', a.done, b.done)

$ node main.js
main starting
a starting
b starting
in b, a.done = false
b done
in a, b.done = true
a done
in main, a.done=true, b.done=true

console.log(__dirname) // /Users/null/meet-nodejs/module

console.log(require('path').dirname(__filename)) // /Users/null/meet-nodejs/module

console.log(__dirname === require('path').dirname(__filename)) // true

// a.js

const EventEmitter = require('events')

module.exports = new EventEmitter()

// Do some work, and after some time emit
// the 'ready' event from the module itself.
setTimeout(() => {
  module.exports.emit('ready')
}, 1000)

const a = require('./a')
a.on('ready', () => {
  console.log('module a is ready')
})

function require(...) {
  // ...
  ((module, exports) => {
    // Your module code here
    exports = some_func;        // re-assigns exports, exports is no longer
                                // a shortcut, and nothing is exported.
    module.exports = some_func; // makes your module export 0
  })(module, module.exports);
  return module;
}

// javascript

var name = 'null仔'

// dart

var name = 'null仔'

// javascript

new Promise((r) => {
  r(1)
})
  .then((res) => ++res)
  .then((res) => ++res)
  .then((res) => console.log(++res)) // 4

// dart

 List<int> list =

   []..addAll([1,2,3,4,5])
     ..replaceRange(0,1,[6])
     ..sort((a,b)=>a-b);

  print(list);  // [2, 3, 4, 5, 6]

值 as 类型

// before
if (foo && foo.bar && foo.bar.baz) {
  // ...
}
// after

if (foo?.bar?.baz) {
  // ...
}

// typescript

let x = foo ?? bar()

// 等价于

let x = foo !== null && foo !== void 0 ? foo : bar()

/*!
 * Lazy Load - JavaScript plugin for lazy loading images
 *
 * Copyright (c) 2007-2019 Mika Tuupola
 *
 * Licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Project home:
 *   https://appelsiini.net/projects/lazyload
 *
 * Version: 2.0.0-rc.2
 *
 */

(function (root, factory) {
  // umd export
  if (typeof exports === "object") {
    module.exports = factory(root);
  } else if (typeof define === "function" && define.amd) {
    define([], factory);
  } else {
    root.LazyLoad = factory(root);
  }
})(
  typeof global !== "undefined" ? global : this.window || this.global,
  function (root) {
    "use strict";

    if (typeof define === "function" && define.amd) {
      root = window;
    }

    const defaults = {
      src: "data-src",
      srcset: "data-srcset",
      selector: ".lazyload",
      root: null,
      rootMargin: "0px",
      threshold: 0,
    };

    /**
     * Merge two or more objects. Returns a new object.
     * @private
     * @param {Boolean}  deep     If true, do a deep (or recursive) merge [optional]
     * @param {Object}   objects  The objects to merge together
     * @returns {Object}          Merged values of defaults and options
     */
    const extend = function () {
      let extended = {};
      let deep = false;
      let i = 0;
      let length = arguments.length;

      /* Check if a deep merge */
      if (Object.prototype.toString.call(arguments[0]) === "[object Boolean]") {
        deep = arguments[0];
        i++;
      }

      /* Merge the object into the extended object */
      let merge = function (obj) {
        for (let prop in obj) {
          if (Object.prototype.hasOwnProperty.call(obj, prop)) {
            /* If deep merge and property is an object, merge properties */
            if (
              deep &&
              Object.prototype.toString.call(obj[prop]) === "[object Object]"
            ) {
              extended[prop] = extend(true, extended[prop], obj[prop]);
            } else {
              extended[prop] = obj[prop];
            }
          }
        }
      };

      /* Loop through each object and conduct a merge */
      for (; i < length; i++) {
        let obj = arguments[i];
        merge(obj);
      }

      return extended;
    };

    function LazyLoad(images, options) {
      // merget default options and options
      this.settings = extend(defaults, options || {});
      this.images = images || document.querySelectorAll(this.settings.selector);
      this.observer = null;
      this.init();
    }

    LazyLoad.prototype = {
      init: function () {
        /* Without observers load everything and bail out early. */
        // 不支持IntersectionObserver API,直接加载图片
        if (!root.IntersectionObserver) {
          this.loadImages();
          return;
        }

        let self = this;
        let observerConfig = {
          root: this.settings.root, // 祖先元素,null或未设置,默认使用顶级文档元素
          rootMargin: this.settings.rootMargin, // 计算交叉时添加到根(root)边界盒bounding box的矩形偏移量
          threshold: [this.settings.threshold], // 阀值(0-1),监听对象的交叉区域与边界区域的比率
        };
        // 使用IntersectionObserver API观察目标元素与root元素的交叉状态
        this.observer = new IntersectionObserver(function (entries) {
          Array.prototype.forEach.call(entries, function (entry) {
            // 目标元素与root元素交叉区域超过threshold阀值
            if (entry.isIntersecting) {
              // 停止监听
              self.observer.unobserve(entry.target);
              // 目前元素 src等属性赋值
              let src = entry.target.getAttribute(self.settings.src);
              let srcset = entry.target.getAttribute(self.settings.srcset);
              // img元素对src赋值,否则对backgroundImage赋值
              if ("img" === entry.target.tagName.toLowerCase()) {
                if (src) {
                  entry.target.src = src;
                }
                if (srcset) {
                  entry.target.srcset = srcset;
                }
              } else {
                entry.target.style.backgroundImage = "url(" + src + ")";
              }
            }
          });
        }, observerConfig);
        Array.prototype.forEach.call(this.images, function (image) {
          // 对目标元素进行监听
          self.observer.observe(image);
        });
      },
      //  加载后销毁
      loadAndDestroy: function () {
        if (!this.settings) {
          return;
        }
        this.loadImages();
        this.destroy();
      },
      // 加载图片
      loadImages: function () {
        if (!this.settings) {
          return;
        }

        let self = this;
        Array.prototype.forEach.call(this.images, function (image) {
          let src = image.getAttribute(self.settings.src);
          let srcset = image.getAttribute(self.settings.srcset);
          if ("img" === image.tagName.toLowerCase()) {
            if (src) {
              image.src = src;
            }
            if (srcset) {
              image.srcset = srcset;
            }
          } else {
            image.style.backgroundImage = "url('" + src + "')";
          }
        });
      },
      // 销毁
      destroy: function () {
        if (!this.settings) {
          return;
        }
        // 解除监听
        this.observer.disconnect();
        this.settings = null;
      },
    };
    // window.lazyload register
    root.lazyload = function (images, options) {
      return new LazyLoad(images, options);
    };
    // jquery plugin register
    if (root.jQuery) {
      const $ = root.jQuery;
      $.fn.lazyload = function (options) {
        options = options || {};
        options.attribute = options.attribute || "data-src";
        new LazyLoad($.makeArray(this), options);
        return this;
      };
    }

    return LazyLoad;
  }
);

Accept-Encoding: gzip, deflate, br

Content-Encoding: gzip

const zlib = require('zlib')
const fs = require('fs')
const gzip = zlib.createGzip()
const inp = fs.createReadStream('zlib.txt')
const out = fs.createWriteStream('zlib.txt.gz')
inp.pipe(gzip).pipe(out)

const zlib = require('zlib')
const fs = require('fs')
const gunzip = zlib.createGunzip()
const inp = fs.createReadStream('./un-zlib.txt.gz')
const out = fs.createWriteStream('un-zlib.txt')
inp.pipe(gunzip).pipe(out)

const fs = require('fs')
const http = require('http')
const zlib = require('zlib')
const filepath = './index.html'

const server = http.createServer((req, res) => {
  const acceptEncoding = req.headers['accept-encoding']
  if (acceptEncoding.includes('gzip')) {
    const gzip = zlib.createGzip()
    res.writeHead(200, {
      'Content-Encoding': 'gzip'
    })
    fs.createReadStream(filepath)
      .pipe(gzip)
      .pipe(res)
  } else {
    fs.createReadStream(filepath).pipe(res)
  }
})

server.listen(4396)

const dns = require('dns')

dns.lookup(`www.github.com`, (err, address, family) => {
  if (err) throw err
  console.log('地址: %j 地址族: IPv%s', address, family) // 地址: "13.229.188.59" 地址族: IPv4
})

const dns = require('dns')

dns.resolve('www.baidu.com', 'A', (err, addresses) => {
  if (err) throw err
  console.log(`IP地址 : ${JSON.stringify(addresses)}`) // IP地址 : ["163.177.151.110","163.177.151.109"]
})

// or

dns.resolve4('www.baidu.com', (err, addresses) => {
  if (err) throw err
  console.log(`IP地址 : ${JSON.stringify(addresses)}`) // IP地址 : ["163.177.151.110","163.177.151.109"]
})

dns.reverse('8.8.8.8', (err, domains) => {
  if (err) throw err
  console.log(domains) // [ 'dns.google' ]
})

dns.lookupService('127.0.0.1', 80, function(err, hostname, service) {
  if (err) throw err
  console.log('主机名：%s，服务类型：%s', hostname, service) // 主机名：localhost，服务类型：http
})

push();
pop();
shift();
unshift();
splice();
sort();
reverse();

function createKeyToOldIdx(children, beginIdx, endIdx) {
  let i, key;
  const map = {};
  for (i = beginIdx; i <= endIdx; ++i) {
    key = children[i].key;
    if (isDef(key)) map[key] = i;
  }
  return map;
}

for (macroTask of macroTaskQueue) {
  // 1. Handle current MACRO-TASK
  handleMacroTask();

  // 2. Handle all MICRO-TASK
  for (microTask of microTaskQueue) {
    handleMicroTask(microTask);
  }
}

const arrayProto = Array.prototype;
export const arrayMethods = Object.create(arrayProto);
const methodsToPatch = [
  "push",
  "pop",
  "shift",
  "unshift",
  "splice",
  "sort",
  "reverse"
];

/**
 * Intercept mutating methods and emit events
 */
methodsToPatch.forEach(function(method) {
  // cache original method
  const original = arrayProto[method];
  def(arrayMethods, method, function mutator(...args) {
    const result = original.apply(this, args);
    const ob = this.__ob__;
    let inserted;
    switch (method) {
      case "push":
      case "unshift":
        inserted = args;
        break;
      case "splice":
        inserted = args.slice(2);
        break;
    }
    if (inserted) ob.observeArray(inserted);
    // notify change
    ob.dep.notify();
    return result;
  });
});

/**
 * Observe a list of Array items.
 */
Observer.prototype.observeArray = function observeArray(items) {
  for (var i = 0, l = items.length; i < l; i++) {
    observe(items[i]);
  }
};

class Vue {
  constructor() {
    //  事件通道调度中心
    this._events = Object.create(null);
  }
  $on(event, fn) {
    if (Array.isArray(event)) {
      event.map(item => {
        this.$on(item, fn);
      });
    } else {
      (this._events[event] || (this._events[event] = [])).push(fn);
    }
    return this;
  }
  $once(event, fn) {
    function on() {
      this.$off(event, on);
      fn.apply(this, arguments);
    }
    on.fn = fn;
    this.$on(event, on);
    return this;
  }
  $off(event, fn) {
    if (!arguments.length) {
      this._events = Object.create(null);
      return this;
    }
    if (Array.isArray(event)) {
      event.map(item => {
        this.$off(item, fn);
      });
      return this;
    }
    const cbs = this._events[event];
    if (!cbs) {
      return this;
    }
    if (!fn) {
      this._events[event] = null;
      return this;
    }
    let cb;
    let i = cbs.length;
    while (i--) {
      cb = cbs[i];
      if (cb === fn || cb.fn === fn) {
        cbs.splice(i, 1);
        break;
      }
    }
    return this;
  }
  $emit(event) {
    let cbs = this._events[event];
    if (cbs) {
      const args = [].slice.call(arguments, 1);
      cbs.map(item => {
        args ? item.apply(this, args) : item.call(this);
      });
    }
    return this;
  }
}

export default {
  name: "keep-alive",
  abstract: true, // 抽象组件属性 ,它在组件实例建立父子关系的时候会被忽略,发生在 initLifecycle 的过程中
  props: {
    include: patternTypes, // 被缓存组件
    exclude: patternTypes, // 不被缓存组件
    max: [String, Number] // 指定缓存大小
  },

  created() {
    this.cache = Object.create(null); // 缓存
    this.keys = []; // 缓存的VNode的键
  },

  destroyed() {
    for (const key in this.cache) {
      // 删除所有缓存
      pruneCacheEntry(this.cache, key, this.keys);
    }
  },

  mounted() {
    // 监听缓存/不缓存组件
    this.$watch("include", val => {
      pruneCache(this, name => matches(val, name));
    });
    this.$watch("exclude", val => {
      pruneCache(this, name => !matches(val, name));
    });
  },

  render() {
    // 获取第一个子元素的 vnode
    const slot = this.$slots.default;
    const vnode: VNode = getFirstComponentChild(slot);
    const componentOptions: ?VNodeComponentOptions =
      vnode && vnode.componentOptions;
    if (componentOptions) {
      // name不在inlcude中或者在exlude中 直接返回vnode
      // check pattern
      const name: ?string = getComponentName(componentOptions);
      const { include, exclude } = this;
      if (
        // not included
        (include && (!name || !matches(include, name))) ||
        // excluded
        (exclude && name && matches(exclude, name))
      ) {
        return vnode;
      }

      const { cache, keys } = this;
      // 获取键，优先获取组件的name字段，否则是组件的tag
      const key: ?string =
        vnode.key == null
          ? // same constructor may get registered as different local components
            // so cid alone is not enough (#3269)
            componentOptions.Ctor.cid +
            (componentOptions.tag ? `::${componentOptions.tag}` : "")
          : vnode.key;
      // 命中缓存,直接从缓存拿vnode 的组件实例,并且重新调整了 key 的顺序放在了最后一个
      if (cache[key]) {
        vnode.componentInstance = cache[key].componentInstance;
        // make current key freshest
        remove(keys, key);
        keys.push(key);
      }
      // 不命中缓存,把 vnode 设置进缓存
      else {
        cache[key] = vnode;
        keys.push(key);
        // prune oldest entry
        // 如果配置了 max 并且缓存的长度超过了 this.max，还要从缓存中删除第一个
        if (this.max && keys.length > parseInt(this.max)) {
          pruneCacheEntry(cache, keys[0], keys, this._vnode);
        }
      }
      // keepAlive标记位
      vnode.data.keepAlive = true;
    }
    return vnode || (slot && slot[0]);
  }
};

export function set(target: Array<any> | Object, key: any, val: any): any {
  // target 为数组
  if (Array.isArray(target) && isValidArrayIndex(key)) {
    // 修改数组的长度, 避免索引>数组长度导致splice()执行有误
    target.length = Math.max(target.length, key);
    // 利用数组的splice变异方法触发响应式
    target.splice(key, 1, val);
    return val;
  }
  // target为对象, key在target或者target.prototype上 且必须不能在 Object.prototype 上,直接赋值
  if (key in target && !(key in Object.prototype)) {
    target[key] = val;
    return val;
  }
  // 以上都不成立, 即开始给target创建一个全新的属性
  // 获取Observer实例
  const ob = (target: any).__ob__;
  // target 本身就不是响应式数据, 直接赋值
  if (!ob) {
    target[key] = val;
    return val;
  }
  // 进行响应式处理
  defineReactive(ob.value, key, val);
  ob.dep.notify();
  return val;
}

const readline = require("readline");

const rl = readline.createInterface({
  //  监听的可读流
  input: process.stdin,
  //  逐行读取（Readline）数据要写入的可写流
  output: process.stdout
});

rl.question("你如何看待 null-cli ？", answer => {
  console.log(`感谢您的宝贵意见：${answer}`);
  rl.close();
});