泛泛而谈

async.js

const { EventEmitter } = require('event-emitter');

function mapAsync(iterable, mapper, option) {
  // consumer 控制 concurrency
}

function filterAsync(iterable, filterer) {
  // promise 控制
}

const map = {
  x1: Promise.resolve(1),
  x2: Promise.reject({
     a: 1,
     b: 2
  })
}

function flatten() {}


class Queue extends EventEmitter {
  constructor() {
     super()
  }
  
  f() {
    this.emit('xxx')
  }
}

binary.js

// 二进制数

var i = 200
i.toString(2)

var j = 0xff
j.toString(2)

// 移位 由于是双精度数，移位之后值更大了
(i << 2)
(j >> 2)

// byte 范围内，可以用 &，将高位的丢弃
(j >> 2) & 0xff

/*
var a byte = 0b001
	var max byte = 0xff
	var i = 0xff
	var j uint = 0xff
	log.Printf("i is %b, i is %b", i, j)
*/

blob.js

/**
* 通过 Blob 可以动态加载资源：API 接口或者手动创建资源
* https://zh.javascript.info/blob
*/
async function main() {
  const content = await fetch('url').then(r => r.blob());
  // https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Basics_of_HTTP/MIME_types
  const blob = new Blob([content], { type: 'text/plain' });
  const url = URL.createObjectURL(blob);
  window.open(url);
  // URL.revokeObjectURL(url);
}

dynamic-load.js

{
  const script = document.createElement('script');
  const content = `import _ from 'https://esm.sh/lodash';
  const m = window._dynamic_module || {}
  m.lodash = _
  `
  const url = URL.createObjectURL(new Blob([content], {
    type: 'text/javascript'
  }))
  script.src = url;
  script.type = 'module'
  script.addEventListener('load', load)
  function load() {
    console.log('module load success')
    this.remove()
  }
  document.head.appendChild(script)
}

glob-asterisk.js

const globby = require("globby");

/***
* extensions 对 * 不生效
**/

/*
paths [
  'dist/200.html',
  'dist/index.html',
  'dist/assets/index.ccce2ca3.css',
  'dist/assets/index.e9a3c359.js'
]
paths1 [
  '200.html',
  '200.txt',
  'demo1.pdf',
  'index.html',
  'assets/index.ccce2ca3.css',
  'assets/index.e9a3c359.js'
]
**/
(async function() {
  const paths = await globby('dist', {
    expandDirectories: {
      extensions: ['html', 'css', 'js'],
    },
  })
  console.log('paths', paths);
  const paths1 = await globby(['*', 'assets'], {
    expandDirectories: {
      extensions: ['html', 'css', 'js'],
    },
    cwd: 'dist'
  })
  console.log('paths1', paths1)
})()

graph.md

整体预览

buffer、logger

多个 goroutine 控制之间的 context

数据库操作

对 docker 机器，数据库实例之间的抽象 (conn) 直接做很多事情的

数据处理与转换

import _ from 'lodash'

// 聚合
_.group()


// 比较差异
_.difference([0, 1, 2, 3],[1, 2, 3, 5, 6]) // [0]

// 求交集∩
_.intersection([0, 1, 2, 3],[1, 2, 3, 5, 6]) // [1, 2, 3]

replace-stream-through2.js

const through2 = require('through2');

function getReplaceStream(searchValue, replaceValue, options) {
  let tail = ''
  return through2(options, function transform(chunk, encoding, callback) {
    const current = tail + chunk
    const data = current.split(searchValue);
    const lastIndex = data.length - 1;
    const last = data[lastIndex];
    const index = last.length - 1;

    data[lastIndex] = last.slice(0, -index);
    tail = last.slice(-index);
    this.push(data.join(replaceValue))
    callback()
  }, function flush(callback) {
    this.push(tail)
    callback()
  })
}

const r1 = getReplaceStream("__VAN_STATIC_BASE_PATH__", "some_special_url")

for (let i = 100; i <= 120; i++) {
  r1.write(String.fromCharCode(i).repeat(10))
  if (i > 110) {
    r1.write('__VAN_STATIC_BASE_PATH__')
  }
}

r1.write('\n')
r1.end()

r1.pipe(process.stdout)

replace-stream.js

const { Transform } = require('stream');

class ReplaceStream extends Transform {
  constructor(searchValue, replaceValue, options) {
    super(options)
    this.searchValue = searchValue
    this.replaceValue = replaceValue
    this.retain = ""
  }

  _transform(chunk, encoding, callback) {
    const current = this.retain + chunk
    const pieces = current.split(this.searchValue);
    const last = pieces.slice(-1)[0]
    // 只需要处理剩余的字符串
    const tailLength = this.searchValue.length - 1
    this.retain = last.slice(-tailLength)

    // 最后一个要去掉一些值
    pieces[pieces.length - 1] = last.slice(0, -tailLength)
    this.push(pieces.join(this.replaceValue))
    callback()
  }

  _flush(callback) {
    this.push(this.retain)
    callback()
  }
}

const r1 = new ReplaceStream("__VAN_STATIC_BASE_PATH__", "some_special_url")


for (let i = 100; i <= 120; i++) {
  r1.write(String.fromCharCode(i).repeat(10))
  if (i > 110) {
    r1.write('__VAN_STATIC_BASE_PATH__')
  }
}

r1.write('\n')
r1.end()

r1.pipe(process.stdout)

replace.js

/***
* 对于一般文本处理场景，RegExp 与 magic-string 可以实现对字符串的快速编辑
*/
import MagicString from 'magic-string'

const regexp = /require\('([^']+)'\)\.default/g

while (true) {
  const result = reg.exec(content)
  if (!result) {
    break
  }
  const [value, filepath] = result;
  const { index } = result;
  out.overwrite(index, index + value.length, JSON.stringify(filepath));
}

/**
* 当然 MagicString 还有其他的 api，
* 比如 append, prepend
**/
console.log(out.toString())

shell.md

Network

• tcpdump 的应用：https://danielmiessler.com/study/tcpdump/#useragent

• nc/netcat：https://zhuanlan.zhihu.com/p/83959309

• socat：https://zhuanlan.zhihu.com/p/347722248

• ifconfig https://stackoverflow.com/questions/29958143/what-are-en0-en1-p2p-and-so-on-that-are-displayed-after-executing-ifconfig

• cidr 的解释：https://www.xinshouzhanzhang.com/cidrip.html

Bash

• bash 的应用：https://github.com/jlevy/the-art-of-command-line

curl 的一些用法

curl http://www.example.com:3000 --resolve www.example.com:3000:127.0.0.1
curl --unix-socket /var/run/docker.sock http://example.com/v1.26/containers/friendly_margulis/stats\?stream\=0

webpack-loadscript.js

var inProgress = {};
var dataWebpackPrefix = "user-trace:";
// loadScript function to load a script via script tag
__webpack_require__.l = (url, done, key, chunkId) => {
	if(inProgress[url]) { inProgress[url].push(done); return; }
	var script, needAttach;
	if(key !== undefined) {
		var scripts = document.getElementsByTagName("script");
		for(var i = 0; i < scripts.length; i++) {
			var s = scripts[i];
			if(s.getAttribute("src") == url || s.getAttribute("data-webpack") == dataWebpackPrefix + key) { script = s; break; }
		}
	}
	if(!script) {
		needAttach = true;
		script = document.createElement('script');

		script.charset = 'utf-8';
		script.timeout = 120;
		if (__webpack_require__.nc) {
			script.setAttribute("nonce", __webpack_require__.nc);
		}
		script.setAttribute("data-webpack", dataWebpackPrefix + key);
		script.src = url;
	}
	inProgress[url] = [done];
	var onScriptComplete = (prev, event) => {
		// avoid mem leaks in IE.
		script.onerror = script.onload = null;
		clearTimeout(timeout);
		var doneFns = inProgress[url];
		delete inProgress[url];
		script.parentNode && script.parentNode.removeChild(script);
		doneFns && doneFns.forEach((fn) => (fn(event)));
		if(prev) return prev(event);
	};
	var timeout = setTimeout(onScriptComplete.bind(null, undefined, { type: 'timeout', target: script }), 120000);
	script.onerror = onScriptComplete.bind(null, script.onerror);
	script.onload = onScriptComplete.bind(null, script.onload);
	needAttach && document.head.appendChild(script);
};