xuhen

1. https://media.licdn.cn/dms/image/C4D12AQFNtlOBwfGrPQ/article-cover_image-shrink_600_2000/0/1582472887635?e=1639612800&v=beta&t=8carkRftCwb-8ZTXe8ZSFh3ewfWRPd2ZrHVgJ8SD9Jg

function permutation(string) {

    if (string.length < 2) return string;

    var permutations = [];

    for (var i = 0; i < string.length; i++) {
        var char = string[i];

xuhen

/**
 * Pushes the items of `iterable` into `sink`, a generator.
 * It uses the generator method `next()` to do so.
 */
function send(iterable: Iterable<any>, sink: any, config?: { log: boolean }) {
  for (const x of iterable) {
    sink.next(x);

    if (config && config.log) {
      console.log('===>', x);

xuhen

/**
 * Returns an iterable that transforms the input sequence
 * of characters into an output sequence of words.
 */
function* tokenize(chars: string) {
  const iterator = chars[Symbol.iterator]();
  let ch;
  do {
    ch = getNextItem(iterator); // (A)

xuhen

// 将form序列化为key1=value1&key2=value2这样的个数，在ajax提交form表单时很有用。

function serialize(form) {
  var parts = [],
    field = null, i,
    len,
    j, optLen, option, optValue;
  for (i = 0, len = form.elements.length; i < len; i++) {
    field = form.elements[i];
    switch (field.type) {

xuhen

// 将浏览器的location上的search字段转换成对象，方便获取值
// ex: ?name=edward&age=34 => {name: 'edward', age: 34}

function getQueryStringArgs() {
    var qs = (location.search.length > 0 ? location.search.substring(1) : ""),
        args = {},
        items = qs.length ? qs.split("&") : [],
        item = null,
        name = null,
        value = null,

xuhen

// 记忆函数，为了更少的计算，以空间换时间。
var memoize = function (func, hasher) {
    var memoize = function (key) {
        var cache = memoize.cache;
        var address = '' + (hasher ? hasher.apply(this, arguments) : key);
        console.log('address', address, key)
        if (!cache[address]) {
            cache[address] = func.apply(this, arguments);
        }
        return cache[address];

xuhen

// 代理实现拖拽功能，并且用自定义事件让触发拖拽逻辑和处理拖拽解耦。

// html
<div id="status"></div>
<div id="box" class="draggable" style="position:absolute; background:red;width: 200px;height: 200px;"> </div>

// js

function EventTarget() {
  this.handlers = {};

xuhen

// html
<select name="title" id="title" style="width:152px;">
  <option value="1">十进制转二进制</option>
  <option value="2">十进制转八进制</option>
  <option value="3">十进制转十六进制</option>
  <option value="4">二进制转十进制</option>
  <option value="5">八进制转十进制</option>
  <option value="6">十六进制转十进制</option>
  <option value="7">二进制转八进制</option>
  <option value="8">八进制转二进制</option>

xuhen

// html
<span id="clock"></span>

// js

(function () {
  const endTime = new Date().getTime() + 10 * 24 * 60 * 60 * 1000;

  const clock = document.getElementById('clock');

xuhen

// ECMA used the name Symbol.iterator. Symbols offer names that are unique and cannot clash 
// with other property names. Also, Symbol.iterator will return an object called an iterator. 
// This iterator will have a method called next which will return an object with keys value and done.

const iterable = {
  [Symbol.iterator]() {
    let step = 0;

    const iterator = {
      next() {