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老前端的戎码生涯

269个JavaScript工具函数 助你提升工作效率(下)

130.blob转file

/**
 *  @param { blob } blob
 *  @param { string } fileName
 */
    export const blobToFile = (blob, fileName) => {
     blob.lastModifiedDate = new Date();
     blob.name = fileName;
     return blob;
     };

131.file转base64

/**
 * @param { * } file 图片文件
 */
export const fileToBase64 = file => {
   let reader = new FileReader();
   reader.readAsDataURL(file);
   reader.onload = function (e) {
       return e.target.result
   };
};

132.递归生成树形结构

export function getTreeData(data, pid, pidName = 'parentId', idName = 'id', childrenName = 'children', key) {
    let arr = [];

    for (let i = 0; i < data.length; i++) {
        if (data[i][pidName] == pid) {
            data[i].key = data[i][idName];
            data[i][childrenName] = getTreeData(data, data[i][idName], pidName, idName, childrenName);
            arr.push(data[i]);
        }
    }

    return arr;

}

133.遍历树节点

export function foreachTree(data, childrenName = 'children', callback) {
    for (let i = 0; i < data.length; i++) {
        callback(data[i]);
        if (data[i][childrenName] && data[i][childrenName].length > 0) {
            foreachTree(data[i][childrenName], childrenName, callback);
        }
    }
}

134.追溯父节点

export function traceParentNode(pid, data, rootPid, pidName = 'parentId', idName = 'id', childrenName = 'children') {
    let arr = [];
    foreachTree(data, childrenName, (node) => {
        if (node[idName] == pid) {
            arr.push(node);
            if (node[pidName] != rootPid) {
                arr = arr.concat(traceParentNode(node[pidName], data, rootPid, pidName, idName));
            }
        }
    });
    return arr; 
}

135.寻找所有子节点

export function traceChildNode(id, data, pidName = 'parentId', idName = 'id', childrenName = 'children') {
    let arr = [];
    foreachTree(data, childrenName, (node) => {
        if (node[pidName] == id) {
            arr.push(node);
            arr = arr.concat(traceChildNode(node[idName], data, pidName, idName, childrenName));
        }
    });
    return arr;
}

136.根据pid生成树形结构

 /**
     *  @param { object } items 后台获取的数据
 *  @param { * } id 数据中的id
  *  @param { * } link 生成树形结构的依据
     */
     export const createTree = (items, id = null, link = 'pid') =>{
     items.filter(item => item[link] === id).map(item => ({ ...item, children: createTree(items, item.id) }));
     };

137.查询数组中是否存在某个元素并返回元素第一次出现的下标

/** 
     * @param {*} item 
     * @param { array } data
       */
       export function inArray(item, data) {
       for (let i = 0; i < data.length; i++) {
           if (item === data[i]) {
           return i;
        }
    }
    return -1;
    }

138.Windows根据详细版本号判断当前系统名称

 /**
     * @param { string } osVersion 
       */
export function OutOsName(osVersion) {
    if(!osVersion){
           return
    }
    let str = osVersion.substr(0, 3);
    if (str === "5.0") {
           return "Win 2000"
       } else if (str === "5.1") {
           return "Win XP"
       } else if (str === "5.2") {
           return "Win XP64"
       } else if (str === "6.0") {
           return "Win Vista"
       } else if (str === "6.1") {
           return "Win 7"
       } else if (str === "6.2") {
           return "Win 8"
       } else if (str === "6.3") {
           return "Win 8.1"
       } else if (str === "10.") {
           return "Win 10"
    } else {
        return "Win"
    }
}

139.判断手机是Andoird还是IOS

/**
 *  0: ios
 *  1: android
 *  2: 其它
 */
   export function getOSType() {
        let u = navigator.userAgent, app = navigator.appVersion;
        let isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1;
        let isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/);
        if (isIOS) {
            return 0;
    }
     if (isAndroid) {
         return 1;
     }
     return 2;
  }

140.函数防抖

 /**
  * @param { function } func
  * @param { number } wait 延迟执行毫秒数
  * @param { boolean } immediate  true 表立即执行,false 表非立即执行
  */
   export function debounce(func,wait,immediate) {
       let timeout;
       return function () {
           let context = this;
           let args = arguments;

           if (timeout) clearTimeout(timeout);
           if (immediate) {
               let callNow = !timeout;
               timeout = setTimeout(() => {
                   timeout = null;
               }, wait);
               if (callNow) func.apply(context, args)
       }
        else {
            timeout = setTimeout(() => {
                func.apply(context, args)
            }, wait);
        }

    }
    }

145.函数节流

/**
 * @param { function } func 函数
 * @param { number } wait 延迟执行毫秒数
 * @param { number } type 1 表时间戳版,2 表定时器版
 */
       export function throttle(func, wait ,type) {
       let previous, timeout;
       if(type===1){
           previous = 0;
       }else if(type===2){
       timeout = null;
       }
       return function() {
           let context = this;
           let args = arguments;
           if(type===1){
               let now = Date.now();

               if (now - previous > wait) {
                   func.apply(context, args);
                   previous = now;
               }
           }else if(type===2){
           if (!timeout) {
                   timeout = setTimeout(() => {
                   timeout = null;
                    func.apply(context, args)
                }, wait)
            }
        }

    }
    }

146.判断数据类型

/**
     * @param {*} target 
       */
       export function type(target) {
       let ret = typeof(target);
       let template = {
           "[object Array]": "array",
           "[object Object]":"object",
           "[object Number]":"number - object",
       "[object Boolean]":"boolean - object",
           "[object String]":'string-object'
       };

       if(target === null) {
           return 'null';
       }else if(ret == "object"){
           let str = Object.prototype.toString.call(target);
           return template[str];
   }else{
        return ret;
    }
    }

147.生成指定范围随机数

/**
  * @param { number } min 
  * @param { number } max 
    */
    export const RandomNum = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;

148.数组乱序

/**
     * @param {array} arr
       */
       export function arrScrambling(arr) {
       let array = arr;
       let index = array.length;
       while (index) {
           index -= 1;
           let randomIndex = Math.floor(Math.random() * index);
           let middleware = array[index];
           array[index] = array[randomIndex];
       array[randomIndex] = middleware
    }
    return array
    }

150.数组交集

 /**
  * @param { array} arr1
  * @param { array } arr2
    */
    export const similarity = (arr1, arr2) => arr1.filter(v => arr2.includes(v));

151.数组中某元素出现的次数

/**

     * @param { array } arr
 * @param {*} value
    */
    export function countOccurrences(arr, value) {
    return arr.reduce((a, v) => v === value ? a + 1 : a + 0, 0);
    }

152.加法函数(精度丢失问题)

/**
     * @param { number } arg1
     * @param { number } arg2
       */
       export function add(arg1, arg2) {
       let r1, r2, m;
   try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
    try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
    m = Math.pow(10, Math.max(r1, r2));
    return (arg1 * m + arg2 * m) / m
    }

153.减法函数(精度丢失问题)

/**
     * @param { number } arg1
     * @param { number } arg2
       */
       export function sub(arg1, arg2) {
       let r1, r2, m, n;
       try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
   try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
    m = Math.pow(10, Math.max(r1, r2));
    n = (r1 >= r2) ? r1 : r2;
    return Number(((arg1 * m - arg2 * m) / m).toFixed(n));
    }

154.除法函数(精度丢失问题)

/**
     * @param { number } num1
     * @param { number } num2
       */
       export function division(num1,num2){
       let t1,t2,r1,r2;
       try{
           t1 = num1.toString().split('.')[1].length;
       }catch(e){
           t1 = 0;
       }
       try{
           t2=num2.toString().split(".")[1].length;
       }catch(e){
           t2=0;
   }
    r1=Number(num1.toString().replace(".",""));
    r2=Number(num2.toString().replace(".",""));
    return (r1/r2)*Math.pow(10,t2-t1);
    }

155.乘法函数(精度丢失问题)

 /**
     * @param { number } num1
     * @param { number } num2
       */
       export function mcl(num1,num2){
   let m=0,s1=num1.toString(),s2=num2.toString();
    try{m+=s1.split(".")[1].length}catch(e){}
    try{m+=s2.split(".")[1].length}catch(e){}
    return Number(s1.replace(".",""))*Number(s2.replace(".",""))/Math.pow(10,m);
    }

156.递归优化(尾递归)

/**
     * @param { function } f
       */
       export function tco(f) {
   let value;
       let active = false;
       let accumulated = [];

       return function accumulator() {
           accumulated.push(arguments);
           if (!active) {
               active = true;
               while (accumulated.length) {
                   value = f.apply(this, accumulated.shift());
               }
               active = false;
           return value;
        }
    };
    }

157.生成随机整数

export function randomNumInteger(min, max) {
    switch (arguments.length) {
        case 1:
            return parseInt(Math.random() * min + 1, 10);
        case 2:
            return parseInt(Math.random() * (max - min + 1) + min, 10);
        default:
            return 0
    }
}

158.去除空格

/**
     * @param { string } str 待处理字符串
     * @param  { number } type 去除空格类型 1-所有空格  2-前后空格  3-前空格 4-后空格 默认为1
       */
       export function trim(str, type = 1) {
       if (type && type !== 1 && type !== 2 && type !== 3 && type !== 4) return;
       switch (type) {
           case 1:
               return str.replace(/\s/g, "");
           case 2:
               return str.replace(/(^\s)|(\s*$)/g, "");
           case 3:
               return str.replace(/(^\s)/g, "");
           case 4:
           return str.replace(/(\s$)/g, "");
        default:
            return str;
    }
    }

159.大小写转换

/**
 * @param { string } str 待转换的字符串
 * @param { number } type 1-全大写 2-全小写 3-首字母大写 其他-不转换
   */

export function turnCase(str, type) {
    switch (type) {
        case 1:
            return str.toUpperCase();
        case 2:
            return str.toLowerCase();
        case 3:
            return str[0].toUpperCase() + str.substr(1).toLowerCase();
        default:
            return str;
    }
}

160.随机16进制颜色 hexColor

/**
 * 方法一
       */
       export function hexColor() {

       let str = '#';
       let arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 'A', 'B', 'C', 'D', 'E', 'F'];
       for (let i = 0; i < 6; i++) {
           let index = Number.parseInt((Math.random() * 16).toString());
       str += arr[index]
    }
    return str;
    }

161.随机16进制颜色 randomHexColorCode

 /**
     * 方法二
       */
   export const randomHexColorCode = () => {
    let n = (Math.random() * 0xfffff * 1000000).toString(16);
    return '#' + n.slice(0, 6);
    };

162.转义html(防XSS攻击)

export const escapeHTML = str =>{
    str.replace(
        /[&<>'"]/g,
        tag =>
            ({
                '&': '&amp;',
                '<': '&lt;',
                '>': '&gt;',
                "'": '&#39;',
                '"': '&quot;'
            }[tag] || tag)
    );
};

163.检测移动/PC设备

export const detectDeviceType = () => { return /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ? 'Mobile' : 'Desktop'; };

164.隐藏所有指定标签

/**
  * 例: hide(document.querySelectorAll('img'))
    */
    export const hideTag = (...el) => [...el].forEach(e => (e.style.display = 'none'));

165.返回指定元素的生效样式

/**
  * @param { element} el  元素节点
  * @param { string } ruleName  指定元素的名称
    */
    export const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName];

166.检查是否包含子元素

 /**
  * @param { element } parent
  * @param { element } child
  * 例:elementContains(document.querySelector('head'), document.querySelector('title')); // true
    */
    export const elementContains = (parent, child) => parent !== child && parent.contains(child);

167.数字超过规定大小加上加号“+”,如数字超过99显示99+

 /**
     * @param { number } val 输入的数字
     * @param { number } maxNum 数字规定界限
       */
       export const outOfNum = (val, maxNum) =>{
       val = val ? val-0 :0;
       if (val > maxNum ) {
       return `${maxNum}+`
    }else{
        return val;
    }
    };

168.如何隐藏所有指定的元素

 const hide = (el) => Array.from(el).forEach(e => (e.style.display = 'none'));

 // 事例:隐藏页面上所有`<img>`元素?
 hide(document.querySelectorAll('img'))

169.如何检查元素是否具有指定的类?

页面DOM里的每个节点上都有一个classList对象,程序员可以使用里面的方法新增、删除、修改节点上的CSS类。使用classList,程序员还可以用它来判断某个节点是否被赋予了某个CSS类。

const hasClass = (el, className) => el.classList.contains(className)

 // 事例
 hasClass(document.querySelector('p.special'), 'special') // true

170.如何切换一个元素的类?

const toggleClass = (el, className) => el.classList.toggle(className)

 // 事例 移除 p 具有类`special`的 special 类
 toggleClass(document.querySelector('p.special'), 'special')

171.如何获取当前页面的滚动位置?

const getScrollPosition = (el = window) => ({
   x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
   y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop
 });

 // 事例
 getScrollPosition(); // {x: 0, y: 200}

172.如何平滑滚动到页面顶部

const scrollToTop = () => {
   const c = document.documentElement.scrollTop || document.body.scrollTop;
   if (c > 0) {
     window.requestAnimationFrame(scrollToTop);
     window.scrollTo(0, c - c / 8);
   }
 }

 // 事例
 scrollToTop()
window.requestAnimationFrame() 告诉浏览器——你希望执行一个动画,并且要求浏览器在下次重绘之前调用指定的回调函数更新动画。该方法需要传入一个回调函数作为参数,该回调函数会在浏览器下一次重绘之前执行。
 requestAnimationFrame:优势:由系统决定回调函数的执行时机。60Hz的刷新频率,那么每次刷新的间隔中会执行一次回调函数,不会引起丢帧,不会卡顿。

window.requestAnimationFrame() 告诉浏览器——你希望执行一个动画,并且要求浏览器在下次重绘之前调用指定的回调函数更新动画。该方法需要传入一个回调函数作为参数,该回调函数会在浏览器下一次重绘之前执行。
 requestAnimationFrame:优势:由系统决定回调函数的执行时机。60Hz的刷新频率,那么每次刷新的间隔中会执行一次回调函数,不会引起丢帧,不会卡顿。

173.如何检查父元素是否包含子元素?

const elementContains = (parent, child) => parent !== child && parent.contains(child);

 // 事例
 elementContains(document.querySelector('head'), document.querySelector('title')); 
 // true
 elementContains(document.querySelector('body'), document.querySelector('body')); 
 // false

174.如何检查指定的元素在视口中是否可见?

 const elementIsVisibleInViewport = (el, partiallyVisible = false) => {
   const { top, left, bottom, right } = el.getBoundingClientRect();
   const { innerHeight, innerWidth } = window;
   return partiallyVisible
     ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) &&
         ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth))
     : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth;
 };

 // 事例
 elementIsVisibleInViewport(el); // 需要左右可见
 elementIsVisibleInViewport(el, true); // 需要全屏(上下左右)可以见

175.如何获取元素中的所有图像?

const getImages = (el, includeDuplicates = false) => {
   const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));
   return includeDuplicates ? images : [...new Set(images)];
 };

 // 事例:includeDuplicates 为 true 表示需要排除重复元素
 getImages(document, true); // ['image1.jpg', 'image2.png', 'image1.png', '...']
 getImages(document, false); // ['image1.jpg', 'image2.png', '...']

176.如何确定设备是移动设备还是台式机/笔记本电脑?

const detectDeviceType = () =>
   /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)
     ? 'Mobile'
     : 'Desktop';

 // 事例
 detectDeviceType(); // "Mobile" or "Desktop"

177.How to get the current URL?

const currentURL = () => window.location.href

 // 事例
 currentURL() // 'https://google.com'

178.如何创建一个包含当前URL参数的对象?

 const getURLParameters = url =>
   (url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(
     (a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a),
     {}
   );

 // 事例
 getURLParameters('http://url.com/page?n=Adam&s=Smith'); // {n: 'Adam', s: 'Smith'}
 getURLParameters('google.com'); // {}

179.如何将一组表单元素转化为对象?

const formToObject = form =>
   Array.from(new FormData(form)).reduce(
     (acc, [key, value]) => ({
       ...acc,

[key]: value

     }),
     {}
   );

 // 事例
 formToObject(document.querySelector('#form')); 
 // { email: 'test@email.com', name: 'Test Name' }

180.如何从对象检索给定选择器指示的一组属性?

const get = (from, ...selectors) =>
   [...selectors].map(s =>
     s
       .replace(/\[([^\[\]]*)\]/g, '.$1.')
       .split('.')
       .filter(t => t !== '')
       .reduce((prev, cur) => prev && prev[cur], from)
   );
 const obj = { selector: { to: { val: 'val to select' } }, target: [1, 2, { a: 'test' }] };

 // Example
 get(obj, 'selector.to.val', 'target[0]', 'target[2].a'); 
 // ['val to select', 1, 'test']

181.如何在等待指定时间后调用提供的函数?

const delay = (fn, wait, ...args) => setTimeout(fn, wait, ...args);
 delay(
   function(text) {
     console.log(text);
   },
   1000,
   'later'
 ); 

 // 1秒后打印 'later'

182.如何在给定元素上触发特定事件且能选择地传递自定义数据?

const triggerEvent = (el, eventType, detail) =>
   el.dispatchEvent(new CustomEvent(eventType, { detail }));

 // 事例
 triggerEvent(document.getElementById('myId'), 'click');
 triggerEvent(document.getElementById('myId'), 'click', { username: 'bob' });
自定义事件的函数有 Event、CustomEvent 和 dispatchEvent
 // 向 window派发一个resize内置事件
 window.dispatchEvent(new Event('resize'))


 // 直接自定义事件,使用 Event 构造函数:
 var event = new Event('build');
 var elem = document.querySelector('#id')
 // 监听事件
 elem.addEventListener('build', function (e) { ... }, false);
 // 触发事件.
 elem.dispatchEvent(event);
CustomEvent 可以创建一个更高度自定义事件,还可以附带一些数据,具体用法如下:
 var myEvent = new CustomEvent(eventname, options);
 其中 options 可以是:
 {
   detail: {
     ...
   },
   bubbles: true,    //是否冒泡
   cancelable: false //是否取消默认事件
 }
其中 detail 可以存放一些初始化的信息,可以在触发的时候调用。其他属性就是定义该事件是否具有冒泡等等功能。
 内置的事件会由浏览器根据某些操作进行触发,自定义的事件就需要人工触发。
 dispatchEvent 函数就是用来触发某个事件:
 element.dispatchEvent(customEvent);

 上面代码表示,在 element 上面触发 customEvent 这个事件。
 // add an appropriate event listener
 obj.addEventListener("cat", function(e) { process(e.detail) });

 // create and dispatch the event
 var event = new CustomEvent("cat", {"detail":{"hazcheeseburger":true}});
 obj.dispatchEvent(event);
 使用自定义事件需要注意兼容性问题,而使用 jQuery 就简单多了:

 // 绑定自定义事件
 $(element).on('myCustomEvent', function(){});

 // 触发事件
 $(element).trigger('myCustomEvent');
 // 此外,你还可以在触发自定义事件时传递更多参数信息:

 $( "p" ).on( "myCustomEvent", function( event, myName ) {
   $( this ).text( myName + ", hi there!" );
 });
 $( "button" ).click(function () {
   $( "p" ).trigger( "myCustomEvent", [ "John" ] );
 });

183.如何从元素中移除事件监听器?

const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts);

 const fn = () => console.log('!');
 document.body.addEventListener('click', fn);
 off(document.body, 'click', fn); 

184.如何获得给定毫秒数的可读格式?

 const formatDuration = ms => {
   if (ms < 0) ms = -ms;
   const time = {
     day: Math.floor(ms / 86400000),
     hour: Math.floor(ms / 3600000) % 24,
     minute: Math.floor(ms / 60000) % 60,
     second: Math.floor(ms / 1000) % 60,
     millisecond: Math.floor(ms) % 1000
   };
   return Object.entries(time)
     .filter(val => val[1] !== 0)
     .map(([key, val]) => `${val} ${key}${val !== 1 ? 's' : ''}`)
     .join(', ');
 };

 // 事例
 formatDuration(1001); // '1 second, 1 millisecond'
 formatDuration(34325055574); 
 // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds'

185.如何获得两个日期之间的差异(以天为单位)?

 const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
   (dateFinal - dateInitial) / (1000 * 3600 * 24);

 // 事例
 getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9

186.如何向传递的URL发出GET请求?

const httpGet = (url, callback, err = console.error) => {
   const request = new XMLHttpRequest();
   request.open('GET', url, true);
   request.onload = () => callback(request.responseText);
   request.onerror = () => err(request);
   request.send();
 };

 httpGet(
   'https://jsonplaceholder.typicode.com/posts/1',
   console.log
 ); 

 // {"userId": 1, "id": 1, "title": "sample title", "body": "my text"}

187.如何对传递的URL发出POST请求?

const httpPost = (url, data, callback, err = console.error) => {
   const request = new XMLHttpRequest();
   request.open('POST', url, true);
   request.setRequestHeader('Content-type', 'application/json; charset=utf-8');
   request.onload = () => callback(request.responseText);
   request.onerror = () => err(request);
   request.send(data);
 };

 const newPost = {
   userId: 1,
   id: 1337,
   title: 'Foo',
   body: 'bar bar bar'
 };
 const data = JSON.stringify(newPost);
 httpPost(
   'https://jsonplaceholder.typicode.com/posts',
   data,
   console.log
 ); 

 // {"userId": 1, "id": 1337, "title": "Foo", "body": "bar bar bar"}

188.如何为指定选择器创建具有指定范围,步长和持续时间的计数器?

const counter = (selector, start, end, step = 1, duration = 2000) => {
   let current = start,
     _step = (end - start) * step < 0 ? -step : step,
     timer = setInterval(() => {
       current += _step;
       document.querySelector(selector).innerHTML = current;
       if (current >= end) document.querySelector(selector).innerHTML = end;
       if (current >= end) clearInterval(timer);
     }, Math.abs(Math.floor(duration / (end - start))));
   return timer;
 };

 // 事例
 counter('#my-id', 1, 1000, 5, 2000); 
 // 让 `id=“my-id”`的元素创建一个2秒计时器

189.如何将字符串复制到剪贴板?

  const el = document.createElement('textarea');
   el.value = str;
   el.setAttribute('readonly', '');
   el.style.position = 'absolute';
   el.style.left = '-9999px';
   document.body.appendChild(el);
   const selected =
     document.getSelection().rangeCount > 0 ? document.getSelection().getRangeAt(0) : false;
   el.select();
   document.execCommand('copy');
   document.body.removeChild(el);
   if (selected) {
     document.getSelection().removeAllRanges();
     document.getSelection().addRange(selected);
   }
 };

 // 事例
 copyToClipboard('Lorem ipsum'); 
 // 'Lorem ipsum' copied to clipboard

190.如何确定页面的浏览器选项卡是否聚焦?

const isBrowserTabFocused = () => !document.hidden;

 // 事例
 isBrowserTabFocused(); // true

191.如何创建目录(如果不存在)?

 const fs = require('fs');
 const createDirIfNotExists = dir => (!fs.existsSync(dir) ? fs.mkdirSync(dir) : undefined);

 // 事例
 createDirIfNotExists('test'); 
这里面的方法大都挺实用,可以解决很多开发过程问题,大家就好好利用起来吧。

192.日期型函数封装

function formatTime(date) {
  if(!!date){
    if(!(date instanceof Date))
    date = new Date(date);
    var month = date.getMonth() + 1
    var day = date.getDate()
    return `${month}月${day}日`;
  }
}

function formatDay(date) {
  if(!!date){
    var year = date.getFullYear()
    var month = date.getMonth() + 1
    var day = date.getDate()
    return [year, month, day].map(formatNumber).join('-');
  }
}

function formatDay2(date) {
  if(!!date){
    var year = date.getFullYear()
    var month = date.getMonth() + 1
    var day = date.getDate()
    return [year, month, day].map(formatNumber).join('/');
  }
}

function formatWeek(date){
  if(!!date){
    var day = date.getDay();
    switch (day) {
      case 0:
        return '周日'
        break;
      case 1:
        return '周一'
        break;
      case 2:
        return '周二'
        break;
      case 3:
        return '周三'
        break;
      case 4:
        return '周四'
        break;
      case 5:
        return '周五'
        break;
      case 6:
        return '周六'
        break;
    }
  }
}

function formatHour(date){
  if(!!date){
    var hour = new Date(date).getHours();
    var minute = new Date(date).getMinutes();
    return [hour, minute].map(formatNumber).join(':');
  }
}

function timestamp(date, divisor=1000){
  if(date == undefined){
    return;
  }else if(typeof date == 'number'){
    return Math.floor(date/divisor);
  }else if(typeof date == 'string'){
    var strs = date.split(/[^0-9]/);
    return Math.floor(+new Date(strs[0] || 0,(strs[1] || 0)-1,strs[2] || 0,strs[3] || 0,strs[4] || 0,strs[5] || 0)/divisor);
  }else if(Date.prototype.isPrototypeOf(date)){
    return Math.floor(+date/divisor);
  }
}

function detimestamp(date){
  if(!!date){
    return new Date(date*1000);
  }
}

function formatNumber(n) {//给在0-9的日期加上0
  n = n.toString()
  return n[1] ? n : '0' + n
}

module.exports = {
  formatTime: formatTime,
  formatDay: formatDay,
  formatDay2: formatDay2,
  formatHour: formatHour,
  formatWeek: formatWeek,
  timestamp: timestamp,
  detimestamp: detimestamp
}

193.时间戳转时间

/** 
 * 时间戳转化为年 月 日 时 分 秒 
 * number: 传入时间戳 
 * format:返回格式,支持自定义,但参数必须与formateArr里保持一致 
*/  
function formatTime(number,format) {  

  var formateArr  = ['Y','M','D','h','m','s'];  
  var returnArr   = [];  

  var date = new Date(number * 1000);  
  returnArr.push(date.getFullYear());  
  returnArr.push(formatNumber(date.getMonth() + 1));  
  returnArr.push(formatNumber(date.getDate()));  

  returnArr.push(formatNumber(date.getHours()));  
  returnArr.push(formatNumber(date.getMinutes()));  
  returnArr.push(formatNumber(date.getSeconds()));  

  for (var i in returnArr)  
  {  
    format = format.replace(formateArr[i], returnArr[i]);  
  }  
  return format;  
} 

//数据转化  
function formatNumber(n) {  
  n = n.toString()  
  return n[1] ? n : '0' + n  
}  

调用示例:

var sjc = 1488481383;//时间戳
console.log(time.formatTime(sjc,'Y/M/D h:m:s'));//转换为日期:2017/03/03 03:03:03
console.log(time.formatTime(sjc, 'h:m'));//转换为日期:03:03

194.js中获取上下文路径

js中获取上下文路径
    //js获取项目根路径,如: http://localhost:8083/uimcardprj
    function getRootPath(){
        //获取当前网址,如: http://localhost:8083/uimcardprj/share/meun.jsp
        var curWwwPath=window.document.location.href;
        //获取主机地址之后的目录,如: uimcardprj/share/meun.jsp
        var pathName=window.document.location.pathname;
        var pos=curWwwPath.indexOf(pathName);
        //获取主机地址,如: http://localhost:8083
        var localhostPaht=curWwwPath.substring(0,pos);
        //获取带"/"的项目名,如:/uimcardprj
        var projectName=pathName.substring(0,pathName.substr(1).indexOf('/')+1);
        return(localhostPaht+projectName);
    }

195.JS大小转化B KB MB GB的转化方法

function conver(limit){  
            var size = "";  
            if( limit < 0.1 * 1024 ){ //如果小于0.1KB转化成B  
                size = limit.toFixed(2) + "B";    
            }else if(limit < 0.1 * 1024 * 1024 ){//如果小于0.1MB转化成KB  
                size = (limit / 1024).toFixed(2) + "KB";              
            }else if(limit < 0.1 * 1024 * 1024 * 1024){ //如果小于0.1GB转化成MB  
                size = (limit / (1024 * 1024)).toFixed(2) + "MB";  
            }else{ //其他转化成GB  
                size = (limit / (1024 * 1024 * 1024)).toFixed(2) + "GB";  
            }  

            var sizestr = size + "";   
            var len = sizestr.indexOf("\.");  
            var dec = sizestr.substr(len + 1, 2);  
            if(dec == "00"){//当小数点后为00时 去掉小数部分  
                return sizestr.substring(0,len) + sizestr.substr(len + 3,2);  
            }  
            return sizestr;  
}  

196.js全屏和退出全屏

function fullScreen() {
      var el = document.documentElement;
      var rfs = el.requestFullScreen || el.webkitRequestFullScreen || el.mozRequestFullScreen || el.msRequestFullScreen;

      //typeof rfs != "undefined" && rfs
      if (rfs) {
        rfs.call(el);
      } else if (typeof window.ActiveXObject !== "undefined") {
        //for IE,这里其实就是模拟了按下键盘的F11,使浏览器全屏
        var wscript = new ActiveXObject("WScript.Shell");
        if (wscript != null) {
          wscript.SendKeys("{F11}");
        }
      }
    }

    //退出全屏
    function exitScreen() {
      var el = document;
      var cfs = el.cancelFullScreen || el.webkitCancelFullScreen || el.mozCancelFullScreen || el.exitFullScreen;

      //typeof cfs != "undefined" && cfs
      if (cfs) {
        cfs.call(el);
      } else if (typeof window.ActiveXObject !== "undefined") {
        //for IE,这里和fullScreen相同,模拟按下F11键退出全屏
        var wscript = new ActiveXObject("WScript.Shell");
        if (wscript != null) {
          wscript.SendKeys("{F11}");
        }
      }
    }

197.格式化时间,转化为几分钟前,几秒钟前

 /**
     * 格式化时间,转化为几分钟前,几秒钟前
     * @param timestamp 时间戳,单位是毫秒
     */
    function timeFormat(timestamp) {
        var mistiming = Math.round((Date.now() - timestamp) / 1000);
        var arrr = ['年', '个月', '星期', '天', '小时', '分钟', '秒'];
        var arrn = [31536000, 2592000, 604800, 86400, 3600, 60, 1];
        for (var i = 0; i < arrn.length; i++) {
            var inm = Math.floor(mistiming / arrn[i]);
            if (inm != 0) {
                return inm + arrr[i] + '前';
            }
        }
    }

198 获取n天之前的日期 getDaysBeforeDate(10) 10天前

/**
     * 获取n天之前的日期 getDaysBeforeDate(10) 10天前
     * @param day 天数
     */
    function getDaysBeforeDate(day) {
        var date = new Date(),
            timestamp, newDate;
        timestamp = date.getTime();
        // 获取三天前的日期
        newDate = new Date(timestamp - day * 24 * 3600 * 1000);
        var year = newDate.getFullYear();
        // 月+1是因为js中月份是按0开始的
        var month = newDate.getMonth() + 1;
        var day = newDate.getDate();
        if (day < 10) { // 如果日小于10,前面拼接0
            day = '0' + day;
        }
        if (month < 10) { // 如果月小于10,前面拼接0
            month = '0' + month;
        }
        return [year, month, day].join('/');
    }

199.获取跳转的classId,通过hash方式获取

/**
     * 获取跳转的classId,通过hash方式获取
     * @return 返回值
     */

    $scope.getQueryString = function() {
        var url= {},
            a = '';
        (a = window.location.search.substr(1)) || (a = window.location.hash.split('?')[1])
        a.split(/&/g).forEach(function(item) {
            url[(item = item.split('='))[0]] = item[1];
        })
        return url
    }

200.过滤器指定字段

function filterArrBySex(data, name) {
        if (!name) {
            console.log(name)
            return data;
        } else {
            return data.filter(function(ele, index, self) {
                if (ele.name.includes(name)) {
                    return ele
                }
            })
        }
    }

201.根据身份证获取出生年月

/**
     * 根据身份证获取出生年月
     * @param idCard
     */
    function getBirthdayFromIdCard(idCard) {
        var birthday = "";
        if (idCard != null && idCard != "") {
            if (idCard.length == 15) {
                birthday = "19" + idCard.substr(6, 6);
            } else if (idCard.length == 18) {
                birthday = idCard.substr(6, 8);
            }

            birthday = birthday.replace(/(.{4})(.{2})/, "$1-$2-");
        }

        return birthday;
    }

202.根据身份证获取年龄

/**
     * 根据身份证获取年龄
     * @param UUserCard
     */
    function IdCard(UUserCard) {
        //获取年龄
        var myDate = new Date();
        var month = myDate.getMonth() + 1;
        var day = myDate.getDate();
        var age = myDate.getFullYear() - UUserCard.substring(6, 10) - 1;
        if (UUserCard.substring(10, 12) < month || UUserCard.substring(10, 12) == month && UUserCard.substring(12, 14) <= day) {
            age++;
        }
        return age
    }
//vue购物车金额结算
window.onload = function() {
    var vm = new Vue({
        el: '#app',
        data: {
            items: [{
                    id: 1,
                    name: "苹果",
                    price: 10,
                    count: 1,
                    url: "http://www.jq22.com/img/cs/500x500-1.png"
                },
                {
                    id: 2,
                    name: "蝴蝶",
                    price: 8,
                    count: 5,
                    url: "http://www.jq22.com/img/cs/500x500-2.png"
                },
                {
                    id: 3,
                    name: "小狗",
                    price: 100,
                    count: 1,
                    url: "http://www.jq22.com/img/cs/500x500-3.png"
                },
                {
                    id: 4,
                    name: "鲜花",
                    price: 10,
                    count: 1,
                    url: "http://www.jq22.com/img/cs/500x500-4.png"
                }
            ],
            search: ""
        },
        methods: {

        },
        filters: { //过滤器
            numFilter: function(data, n) { //data==item.price 当前过滤的数据 n==2
                return "¥" + data.toFixed(n)
            }
        },
        computed: { //计算属性
            totalCount: function() {
                var n = 0;
                this.items.forEach((v, i) => {
                    n += v.count
                });
                return n;
            },
            totalPrice: function() {
                var money = 0;
                this.items.forEach((v, i) => {
                    money += v.count * v.price
                });
                return money;
            },
            searchFor: function() {
                if (!this.search) {
                    return this.items
                }
                return this.items.filter((v, i) => {
                    if (v.name.indexOf(this.search) !== -1) { //匹配成功
                        return v
                    }
                })
            }

        }
    })
}

//设置iframe高度
function setIframeHeight(sonH) { //debugger;            
    var height = 0;
    //比较父子页面高度,以高度更大的为准
    var parentH = $(window).height(); //iframe最小高度应为浏览器视口高度,否则门户管理页面弹窗大小会受限制
    height = parentH > sonH ? parentH : sonH;
    $('#mainIframe').height(height);

    //子页面有传值过来,覆盖iframe的最小高度-2000px
    $("#mainIframe").css("min-height", 'auto');
    $(".body-bg").css("height", height + 200);
    try {
        var childBody = $("#mainIframe")[0].contentWindow.document.getElementsByTagName("body")[0];
        //childBody.style.minHeight = height + "px";
    } catch (error) {
        if (error.message.indexOf("Blocked from frame") > -1) console.warn("当前页面存在跨域!");
    }
}


(function($) {
    $("#username").keyup(function(event) {
        if (event.keyCode == 13) $("#password").focus().select();
    });
    $("#password").keyup(function(event) {
        if (event.keyCode == 13) $("#login-button").click();
    });
})(jQuery);


//回到顶部
function goTop() {
    window.scrollTo({
        top: 0,
        behavior: 'smooth',
    });
}

window.onscroll = function() {
    var t = document.documentElement.scrollTop;
    if (t > 50) {
        $(".toTop").fadeIn();
    } else {
        $(".toTop").fadeOut();
    }
}


function urlAnalysis() {
    var url = window.location.href;
    var paraString = url.substring(url.indexOf("?") + 1, url.length);
    var indexFirst = paraString.indexOf("&");
    var paraStringTitle = paraString.slice(0, indexFirst);
    paraStringElse = paraString.slice(indexFirst + 1, paraString.length);
    var paraStringUrl = paraStringElse;

    //区分是否传参:functionId
    if (paraString.indexOf("functionId") > -1) {
        var indexSecond = paraStringElse.indexOf("&");
        var paraStringFId = paraStringElse.slice(0, indexSecond);

        var functionId = paraStringFId.split("=")[1];
        var $body = angular.element(document.body);
        var $rootScope = $body.scope().$root;
        $rootScope.navFunctionId = functionId;

        paraStringUrl = paraStringElse.slice(indexSecond + 1, paraStringElse.length);
    }

    var title = paraStringTitle.split("=")[1] === "undefined" ? "" : decodeURI(paraStringTitle.split("=")[1]);
    var indexUrl = paraStringUrl.indexOf("=");
    var iframeUrl = paraStringUrl.slice(indexUrl + 1, paraStringUrl.length);

    document.title = title;
    $("#mainIframe").attr("src", iframeUrl);
}



// 监听enter按下事件,页面跳转
$scope.enterEvent = function(e) {
    var keycode = window.event ? e.keyCode : e.which;
    if (keycode == 13) {
        console.log($scope.searchVal)
        console.log('监听成功')
        var baseUrl = '#/pages/knowlege/knowlegeSeach.html'
        window.open(baseUrl)
    }
};


function showDate() {
    var myDate = new Date();
    var year = myDate.getFullYear();
    var month = myDate.getMonth() + 1;
    month = month < 10 ? '0' + month : month;
    var date = myDate.getDate();
    date = date < 10 ? '0' + date : date;
    var weekDay = myDate.getDay();

    switch (weekDay) {
        case 0:
            weekDay = "天";
            break;
        case 1:
            weekDay = "一";
            break;
        case 2:
            weekDay = "二";
            break;
        case 3:
            weekDay = "三";
            break;
        case 4:
            weekDay = "四";
            break;
        case 5:
            weekDay = "五";
            break;
        case 6:
            weekDay = "六";
            break;
            "name"
    }

    $scope.year = year;
    $scope.month = month;
    $scope.date = date;
    $scope.weekDay = weekDay;
}


//获取跳转的classId,通过hash方式获取
$scope.getQueryString = function() {
    var obg = {},
        a = '';
    (a = window.location.search.substr(1)) || (a = window.location.hash.split('?')[1])
    a.split(/&/g).forEach(function(item) {
        obg[(item = item.split('='))[0]] = item[1];
    })
    return obg
}
var classId = $scope.getQueryString();

203.原生js滑块验证

//event.clientX:鼠标点下的点到左侧x轴的距离
window.onload = function() {
    //事件处理  onmousedown  onmousemove  onmouseup
    var box = document.querySelector(".box")
    var btn = document.querySelector(".btn")
    var bg = document.querySelector(".bg")
    var text1 = document.querySelector(".text")
    //封装的选择器 声明式函数可以提升
    //            function fun(){
    //                
    //            }
    var flag = false; //标记
    btn.onmousedown = function(event) {
        var downx = event.clientX; //按下后获取的与x轴的距离
        btn.onmousemove = function(e) {
            var movex = e.clientX - downx; //滑块滑动的距离
            //移动的范围
            if (movex > 0) {
                this.style.left = movex + "px";
                bg.style.width = movex + "px";
                if (movex >= box.offsetWidth - 40) {
                    //验证成功
                    flag = true
                    text1.innerHTML = "验证成功"
                    text1.style.color = "#fff"
                    //清除事件
                    btn.onmousedown = null;
                    btn.onmousemove = null;
                }
            }
        }
    }
    //松开事件
    btn.onmouseup = function() {
        //清除事件
        btn.onmousemove = null;
        if (flag) return;
        this.style.left = 0;
        bg.style.width = 0 + "px";
    }
}

204.纯 js无限加载瀑布(原创)

//随机[m,n]之间的整数 封装
function randomNumber(m, n) {
    return Math.floor(Math.random() * (n - m + 1) + m);
}
//随机颜色 封装
function randomColor() {
    return "rgb(" + randomNumber(0, 255) + "," + randomNumber(0, 255) + "," + randomNumber(0, 255) + ")";
}

//获取当前的scrollTop 
var scrollTopDistance;
//获取所有的ul 
var uls = document.querySelectorAll("ul");
var i = 0;
var k = i;

function waterFall() {
    for (i = k; i < k + 4; i++) {
        //创建li 
        var li = document.createElement("li");
        //随机颜色 
        li.style.backgroundColor = randomColor();
        //随机高度 
        li.style.height = randomNumber(120, 400) + "px";
        //手动转换为字符串 
        li.innerHTML = i + 1 + "";
        //插入到对应的ul中 
        //判断哪个ul的高度低,该次创建的li就插入到此ul中 
        var index = 0; //记录下标 
        for (var j = 0; j < uls.length; j++) {
            if (uls[j].offsetHeight < uls[index].offsetHeight) {
                index = j;
            }
        }
        //将元素节点插入文档中 
        uls[index].appendChild(li);
    }
    k = i;
    return uls[index].offsetHeight;
}
waterFall();
//鼠标滚轮事件,由于右侧没有滚轮,所以使用onmousewheel事件
window.onmousewheel = function() {
    //获取窗口的高度,要兼容浏览器
    var windowH = document.documentElement.clientHeight;
    //滚轮于top的距离,要兼容浏览器
    var scrollH = document.documentElement.scrollTop ||
        document.body.scrollTop;
    //获取窗口的可见高度
    var documentH = document.documentElement.scrollHeight ||
        document.body.scrollHeight;
    //窗口的高度 + 滚轮与顶部的距离 > 窗口的可见高度-200
    if (windowH + scrollH > documentH - 200) {
        //执行此函数 
        waterFall()
    }
}

205.jQuery两个元素比较高度

$(*function* () {
  *var* w_max = 0;
  *//求最大高度*
  $("#MenuNavigation li").each(*function* () {
    *var* w = $(*this*).innerWidth();
    w_max = w > w_max ? w : w_max;
  })
  $("#MenuNavigation li").width(w_max)
  *//将最大高度赋值给所有元素,*
})

206.js定时清除缓存,存储缓存,获取缓存

// 封装本地存储的方法
export const storage = {
  set: function(variable, value, ttl_ms) {
    var data = { value: value, expires_at: new Date(ttl_ms).getTime() };
    localStorage.setItem(variable.toString(), JSON.stringify(data));
  },
  get: function(variable) {
    var data = JSON.parse(localStorage.getItem(variable.toString()));
    if (data !== null) {
      debugger
      if (data.expires_at !== null && data.expires_at < new Date().getTime()) {
        localStorage.removeItem(variable.toString());
      } else {
        return data.value;
      }
    }
    return null;
  },
  remove(key) {
    localStorage.removeItem(key);
  }
}

207.数组降维

//数组降维
reduceDimension(arr) {
      var reduced = [];
      for (var i = 0; i < arr.length; i++) {
        reduced = reduced.concat(arr[i]);
      }
      return reduced;
}

208.设置cookie,获取cookie,删除cookie

var cookieUtil = {
  getCookie: function (name) {
    var arrCookie = document.cookie.split("; ");
    for (var i = 0; i < arrCookie.length; i++) {
      var cookieItem = arrCookie[i].split('=');
      if (cookieItem[0] == name) {
        return cookieItem[1];
      }
    }
    return undefined;
  },
  setCookie: function (name, value, expires, path, domain, secure) {
    var cookieText = encodeURIComponent(name) + "=" +
      encodeURIComponent(value);
    if (expires instanceof Date) {
      cookieText += "; expires=" + expires.toGMTString();
    }
    if (path) {
      cookieText += "; path=" + path;
    }
    if (domain) {
      cookieText += "; domain=" + domain;
    }
    if (secure) {
      cookieText += "; secure";
    }
    document.cookie = cookieText;
  },
  removeCookie: function (name, path, domain, secure) {
    this.set(name, "", new Date(0), path, domain, secure);
  }
} 

209.判读是否为外链

/**

 * @description 判读是否为外链
 * @param path
 * @returns {boolean}
   */
   export function isExternal(path) {
     return /^(https?:|mailto:|tel:)/.test(path);
   }

210.校验密码是否小于6位

/**
     * @description 校验密码是否小于6位
     * @param str
     * @returns {boolean}
       */
       export function isPassword(str) {
         return str.length >= 6;
       }

211.判断是否为数字

/**

   * @description 判断是否为数字
   * @param value
 * @returns {boolean}
    */
    export function isNumber(value) {
      const reg = /^[0-9]*$/;
      return reg.test(value);
    }

## 212.判断是否是名称

 /**

   * @description 判断是否是名称
   * @param value
 * @returns {boolean}
    */
    export function isName(value) {
      const reg = /^[\u4e00-\u9fa5a-zA-Z0-9]+$/;
      return reg.test(value);
    }

213.判断是否为IP

/**

   * @description 判断是否为IP
   * @param ip
 * @returns {boolean}
    */
    export function isIP(ip) {
      const reg = /^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/;
      return reg.test(ip);
    }

214.判断是否是传统网站

 /**

   * @description 判断是否是传统网站
   * @param url
 * @returns {boolean}
    */
    export function isUrl(url) {
      const reg = /^(https?|ftp):\/\/([a-zA-Z0-9.-]+(:[a-zA-Z0-9.&%$-]+)*@)*((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]?)(\.(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])){3}|([a-zA-Z0-9-]+\.)*[a-zA-Z0-9-]+\.(com|edu|gov|int|mil|net|org|biz|arpa|info|name|pro|aero|coop|museum|[a-zA-Z]{2}))(:[0-9]+)*(\/($|[a-zA-Z0-9.,?'\\+&%$#=~_-]+))*$/;
      return reg.test(url);
    }

215.判断是否是小写字母

 /**

   * @description 判断是否是小写字母
   * @param str
 * @returns {boolean}
    */
    export function isLowerCase(str) {
      const reg = /^[a-z]+$/;
      return reg.test(str);
    }

216.判断是否是大写字母

/**

   * @description 判断是否是大写字母
   * @param str
 * @returns {boolean}
    */
    export function isUpperCase(str) {
      const reg = /^[A-Z]+$/;
      return reg.test(str);
    }

217.判断是否是大写字母开头

/**

   * @description 判断是否是大写字母开头
   * @param str
 * @returns {boolean}
    */
    export function isAlphabets(str) {
      const reg = /^[A-Za-z]+$/;
      return reg.test(str);
    }

218.判断是否是字符串

/**

   * @description 判断是否是字符串
 * @param str
  * @returns {boolean}
    */
    export function isString(str) {
      return typeof str === "string" || str instanceof String;
    }

219.判断是否是数组

 /**

   * @description 判断是否是数组
     * @param arg
   * @returns {arg is any[]|boolean}
     */
   export function isArray(arg) {
      if (typeof Array.isArray === "undefined") {
    return Object.prototype.toString.call(arg) === "[object Array]";
      }
      return Array.isArray(arg);
    }

220.判断是否是端口号

/**

   * @description 判断是否是端口号
   * @param str
 * @returns {boolean}
    */
    export function isPort(str) {
      const reg = /^([0-9]|[1-9]\d|[1-9]\d{2}|[1-9]\d{3}|[1-5]\d{4}|6[0-4]\d{3}|65[0-4]\d{2}|655[0-2]\d|6553[0-5])$/;
      return reg.test(str);
    }

221.判断是否是手机号

 /**

   * @description 判断是否是手机号
   * @param str
 * @returns {boolean}
    */
    export function isPhone(str) {
      const reg = /^1\d{10}$/;
      return reg.test(str);
    }

222.判断是否是身份证号(第二代)

 /**

   * @description 判断是否是身份证号(第二代)
   * @param str
 * @returns {boolean}
    */
    export function isIdCard(str) {
      const reg = /^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$/;
      return reg.test(str);
    }

223.判断是否是邮箱

/**

   * @description 判断是否是邮箱
   * @param str
 * @returns {boolean}
    */
    export function isEmail(str) {
      const reg = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/;
      return reg.test(str);
    }

## 224.判断是否中文

 /**

   * @description 判断是否中文
   * @param str
 * @returns {boolean}
    */
    export function isChina(str) {
      const reg = /^[\u4E00-\u9FA5]{2,4}$/;
      return reg.test(str);
    }

## 225.判断是否为空

/**

   * @description 判断是否为空
     * @param str
     * @returns {boolean}
       */
       export function isBlank(str) {
         return (
     str == null ||
   false ||
    str === "" ||
    str.trim() === "" ||
    str.toLocaleLowerCase().trim() === "null"
      );
    }

## 226.判断是否为固话

 /**

   * @description 判断是否为固话
   * @param str
 * @returns {boolean}
    */
    export function isTel(str) {
      const reg = /^(400|800)([0-9\\-]{7,10})|(([0-9]{4}|[0-9]{3})(-| )?)?([0-9]{7,8})((-| |转)*([0-9]{1,4}))?$/;
      return reg.test(str);
    }

## 227.判断是否为数字且最多两位小数

/**

   * @description 判断是否为数字且最多两位小数
   * @param str
 * @returns {boolean}
    */
    export function isNum(str) {
      const reg = /^\d+(\.\d{1,2})?$/;
      return reg.test(str);
    }

## 228.判断经度 -180.0~+180.0(整数部分为0~180,必须输入1到5位小数)

 /**

   * @description 判断经度 -180.0~+180.0(整数部分为0~180,必须输入1到5位小数)
   * @param str
 * @returns {boolean}
    */
    export function isLongitude(str) {
      const reg = /^[-|+]?(0?\d{1,2}\.\d{1,5}|1[0-7]?\d{1}\.\d{1,5}|180\.0{1,5})$/;
      return reg.test(str);
    }

## 229.判断纬度 -90.0~+90.0(整数部分为0~90,必须输入1到5位小数)

/**

   * @description 判断纬度 -90.0~+90.0(整数部分为0~90,必须输入1到5位小数)
   * @param str
 * @returns {boolean}
    */
    export function isLatitude(str) {
      const reg = /^[-|+]?([0-8]?\d{1}\.\d{1,5}|90\.0{1,5})$/;
      return reg.test(str);
    }

## 230.rtsp校验只要有rtsp://

/**

   * @description rtsp校验,只要有rtsp://
   * @param str
   * @returns {boolean}
     */
   export function isRTSP(str) {
      const reg = /^rtsp:\/\/([a-z]{0,10}:.{0,10}@)?(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/;
      const reg1 = /^rtsp:\/\/([a-z]{0,10}:.{0,10}@)?(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5]):[0-9]{1,5}/;
      const reg2 = /^rtsp:\/\/([a-z]{0,10}:.{0,10}@)?(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\//;
      return reg.test(str) || reg1.test(str) || reg2.test(str);
    }

231.判断IE浏览器版本和检测是否为非IE浏览器

function IEVersion() {
    var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串  
    var isIE = userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1; //判断是否IE<11浏览器  
    var isEdge = userAgent.indexOf("Edge") > -1 && !isIE; //判断是否IE的Edge浏览器  
    var isIE11 = userAgent.indexOf('Trident') > -1 && userAgent.indexOf("rv:11.0") > -1;
    if (isIE) {
        var reIE = new RegExp("MSIE (\\d+\\.\\d+);");
        reIE.test(userAgent);
        var fIEVersion = parseFloat(RegExp["$1"]);
        if (fIEVersion == 7) {
            return 7;
        } else if (fIEVersion == 8) {
            return 8;
        } else if (fIEVersion == 9) {
            return 9;
        } else if (fIEVersion == 10) {
            return 10;
        } else {
            return 6; //IE版本<=7
        }
    } else if (isEdge) {
        return 'edge'; //edge
    } else if (isIE11) {
        return 11; //IE11  
    } else {
        return -1; //不是ie浏览器
    }
}

232.数组去重

方案一:Set + …

function noRepeat(arr) {
  return [...new Set(arr)];
}
noRepeat([1,2,3,1,2,3])

方案二:Set + Array.from

function noRepeat(arr) {
  return Array.from(new Set(arr));
}
noRepeat([1,2,3,1,2,3])

方案三:双重遍历比对下标

function noRepeat(arr) {
  return arr.filter((v, idx)=>idx == arr.lastIndexOf(v))
}
noRepeat([1,2,3,1,2,3])

方案四:单遍历 + Object 特性

Object 的特性是 Key 不会重复。 这里使用 values 是因为可以保留类型,keys 会变成字符串。

function noRepeat(arr) {
  return Object.values(arr.reduce((s,n)=>{
    s[n] = n;
    return s
  },{}))
}
noRepeat([1,2,3,1,2,3])

后记

针对于上述的方案,还有其他变种实现。

233.查找数组最大

方案一:Math.max + …

function arrayMax(arr) {
  return Math.max(...arr);
}
arrayMax([-1,-4,5,2,0])

方案二:Math.max + apply

function arrayMax(arr) {
  return Math.max.apply(Math, arr)
}
arrayMax([-1,-4,5,2,0])

方案三:Math.max + 遍历

function arrayMax(arr) {
  return arr.reduce((s,n)=>Math.max(s, n))
}
arrayMax([-1,-4,5,2,0])

方案四:比较、条件运算法 + 遍历

function arrayMax(arr) {
  return arr.reduce((s,n)=>s>n?s:n)
}
arrayMax([-1,-4,5,2,0])

方案五:排序

function arrayMax(arr) {
  return arr.sort((n,m)=>m-n)[0]
}
arrayMax([-1,-4,5,2,0])

234.查找数组最小

同上,不明白为什么要分成两个题目

  1. Math.max 换成 Math.min
  2. s&gt;n?s:n 换成 s(n,m)=>m-n换成(n,m)=>n-m,或者直接取最后一个元素</ol>¨K273K¨K274K¨G108G¨K275K¨G109G¨K276K¨G110G¨K277K¨K278K¨G111G¨K279K¨G112G¨K280K¨K281K¨G113G¨K282K¨G114G¨K283K¨K284K他原文有问题,以下方法的4,5没有返回¨G115G需要再操作一遍¨G116G¨K285K算是方案1的变种吧,优化了includes` 的性能。

237.返回两个数组中相同的元素

方案一:filter + includes

function intersection(arr1, arr2) {
  return arr2.filter((v) => arr1.includes(v));
}
intersection([1,2,3], [3,4,5,2])

方案二:同理变种用 hash

function intersection(arr1, arr2) {
    var set = new Set(arr2)
  return arr1.filter((v) => set.has(v));
}
intersection([1,2,3], [3,4,5,2])

238.从右删除 n 个元素

方案一:slice

 function dropRight(arr, n = 0) {
  return n < arr.length ? arr.slice(0, arr.length - n) : [];
}
dropRight([1,2,3,4,5], 2)

方案二: splice

 function dropRight(arr, n = 0) {
  return arr.splice(0, arr.length - n)
}
dropRight([1,2,3,4,5], 2)

方案三: slice 另一种

 function dropRight(arr, n = 0) {
  return arr.slice(0, -n)
}
dropRight([1,2,3,4,5], 2)

方案四: 修改 length

  function dropRight(arr, n = 0) {
    arr.length = Math.max(arr.length - n, 0)
    return arr
}
dropRight([1,2,3,4,5], 2)

239.截取第一个符合条件的元素及其以后的元素

方案一:slice + 循环

  function dropElements(arr, fn) {
  while (arr.length && !fn(arr[0])) arr = arr.slice(1);
  return arr;
}
dropElements([1,2,3,4,5,1,2,3], (v) => v == 2)

方案二:findIndex + slice

  function dropElements(arr, fn) {
  return arr.slice(Math.max(arr.findIndex(fn), 0));
}
dropElements([1,2,3,4,5,1,2,3], (v) => v === 3)

方案三:splice + 循环

  function dropElements(arr, fn) {
  while (arr.length && !fn(arr[0])) arr.splice(0,1);
  return arr;
}
dropElements([1,2,3,4,5,1,2,3], (v) => v == 2)

240.返回数组中下标间隔 nth 的元素

方案一:filter

 function everyNth(arr, nth) {
  return arr.filter((v, i) => i % nth === nth - 1);
}
everyNth([1,2,3,4,5,6,7,8], 2)

方案二:方案一修改判断条件

 function everyNth(arr, nth) {
  return arr.filter((v, i) => (i+1) % nth === 0);
}
everyNth([1,2,3,4,5,6,7,8], 2)

241.返回数组中第 n 个元素(支持负数)

方案一:slice

  function nthElement(arr, n = 0) {
  return (n >= 0 ? arr.slice(n, n + 1) : arr.slice(n))[0];
}
nthElement([1,2,3,4,5], 0)
nthElement([1,2,3,4,5], -1)

方案二:三目运算符

 function nthElement(arr, n = 0) {
  return (n >= 0 ? arr[0] : arr[arr.length + n])
}
nthElement([1,2,3,4,5], 0)
nthElement([1,2,3,4,5], -1)

242.返回数组头元素

方案一:

  function head(arr) {
  return arr[0];
}
head([1,2,3,4])

方案二:

function head(arr) {
  return arr.slice(0,1)[0];
}
head([1,2,3,4])

243.返回数组末尾元素

方案一:

 function last(arr) {
  return arr[arr.length - 1];
}

方案二:

 function last(arr) {
  return arr.slice(-1)[0];
}
last([1,2,3,4,5])

245.数组乱排

方案一:洗牌算法

  function shuffle(arr) {
  let array = arr;
  let index = array.length;

  while (index) {
    index -= 1;
    let randomInedx = Math.floor(Math.random() * index);
    let middleware = array[index];
    array[index] = array[randomInedx];
    array[randomInedx] = middleware;
  }

  return array;
}
shuffle([1,2,3,4,5])

方案二:sort + random

  function shuffle(arr) {
  return arr.sort((n,m)=>Math.random() - .5)
}
shuffle([1,2,3,4,5])

246.伪数组转换为数组

方案一:Array.from

 Array.from({length: 2})

方案二:prototype.slice

  Array.prototype.slice.call({length: 2,1:1})

方案三:prototype.splice

 Array.prototype.splice.call({length: 2,1:1},0)

浏览器对象 BOM

195.判读浏览器是否支持 CSS 属性

  /**
 * 告知浏览器支持的指定css属性情况
 * @param {String} key - css属性,是属性的名字,不需要加前缀
 * @returns {String} - 支持的属性情况
 */
function validateCssKey(key) {
  const jsKey = toCamelCase(key); // 有些css属性是连字符号形成
  if (jsKey in document.documentElement.style) {
    return key;
  }
  let validKey = "";
  // 属性名为前缀在js中的形式,属性值是前缀在css中的形式
  // 经尝试,Webkit 也可是首字母小写 webkit
  const prefixMap = {
    Webkit: "-webkit-",
    Moz: "-moz-",
    ms: "-ms-",
    O: "-o-",
  };
  for (const jsPrefix in prefixMap) {
    const styleKey = toCamelCase(`${jsPrefix}-${jsKey}`);
    if (styleKey in document.documentElement.style) {
      validKey = prefixMap[jsPrefix] + key;
      break;
    }
  }
  return validKey;
}

/**
 * 把有连字符号的字符串转化为驼峰命名法的字符串
 */
function toCamelCase(value) {
  return value.replace(/-(\w)/g, (matched, letter) => {
    return letter.toUpperCase();
  });
}

/**
 * 检查浏览器是否支持某个css属性值(es6版)
 * @param {String} key - 检查的属性值所属的css属性名
 * @param {String} value - 要检查的css属性值(不要带前缀)
 * @returns {String} - 返回浏览器支持的属性值
 */
function valiateCssValue(key, value) {
  const prefix = ["-o-", "-ms-", "-moz-", "-webkit-", ""];
  const prefixValue = prefix.map((item) => {
    return item + value;
  });
  const element = document.createElement("div");
  const eleStyle = element.style;
  // 应用每个前缀的情况,且最后也要应用上没有前缀的情况,看最后浏览器起效的何种情况
  // 这就是最好在prefix里的最后一个元素是''
  prefixValue.forEach((item) => {
    eleStyle[key] = item;
  });
  return eleStyle[key];
}

/**
 * 检查浏览器是否支持某个css属性值
 * @param {String} key - 检查的属性值所属的css属性名
 * @param {String} value - 要检查的css属性值(不要带前缀)
 * @returns {String} - 返回浏览器支持的属性值
 */
function valiateCssValue(key, value) {
  var prefix = ["-o-", "-ms-", "-moz-", "-webkit-", ""];
  var prefixValue = [];
  for (var i = 0; i < prefix.length; i++) {
    prefixValue.push(prefix[i] + value);
  }
  var element = document.createElement("div");
  var eleStyle = element.style;
  for (var j = 0; j < prefixValue.length; j++) {
    eleStyle[key] = prefixValue[j];
  }
  return eleStyle[key];
}

function validCss(key, value) {
  const validCss = validateCssKey(key);
  if (validCss) {
    return validCss;
  }
  return valiateCssValue(key, value);
}

https://segmentfault.com/a/11… 它里面有 forEach。

247.返回当前网页地址

方案一:location

  function currentURL() {
  return window.location.href;
}
currentURL()

方案二:a 标签

  function currentURL() {
  var el = document.createElement('a')
  el.href = ''
  return el.href
}
currentURL()

获取滚动条位置

 function getScrollPosition(el = window) {
  return {
    x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
    y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop,
  };
}

248.获取 url 中的参数

方案一:正则 + reduce

function getURLParameters(url) {
  return url
    .match(/([^?=&]+)(=([^&]*))/g)
    .reduce(
      (a, v) => (
        (a[v.slice(0, v.indexOf("="))] = v.slice(v.indexOf("=") + 1)), a
      ),
      {}
    );
}
getURLParameters(location.href)

方案二:split + reduce

 function getURLParameters(url) {
  return url
    .split('?') //取?分割
    .slice(1) //不要第一部分
    .join() //拼接
    .split('&')//&分割
    .map(v=>v.split('=')) //=分割
    .reduce((s,n)=>{s[n[0]] = n[1];return s},{})
}
getURLParameters(location.href)
// getURLParameters('')

方案三: URLSearchParams

249.页面跳转,是否记录在 history 中

方案一:

  function redirect(url, asLink = true) {
  asLink ? (window.location.href = url) : window.location.replace(url);
}

方案二:

 function redirect(url, asLink = true) {
  asLink ? window.location.assign(url) : window.location.replace(url);
}

250.滚动条回到顶部动画

方案一: c – c / 8

c 没有定义

 function scrollToTop() {
  const scrollTop =
    document.documentElement.scrollTop || document.body.scrollTop;
  if (scrollTop > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, c - c / 8);
  } else {
    window.cancelAnimationFrame(scrollToTop);
  }
}
scrollToTop()

修正之后

  function scrollToTop() {
  const scrollTop =
    document.documentElement.scrollTop || document.body.scrollTop;
  if (scrollTop > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, scrollTop - scrollTop / 8);
  } else {
    window.cancelAnimationFrame(scrollToTop);
  }
}
scrollToTop()

251.复制文本

方案一:

  function copy(str) {
  const el = document.createElement("textarea");
  el.value = str;
  el.setAttribute("readonly", "");
  el.style.position = "absolute";
  el.style.left = "-9999px";
  el.style.top = "-9999px";
  document.body.appendChild(el);
  const selected =
    document.getSelection().rangeCount > 0
      ? document.getSelection().getRangeAt(0)
      : false;
  el.select();
  document.execCommand("copy");
  document.body.removeChild(el);
  if (selected) {
    document.getSelection().removeAllRanges();
    document.getSelection().addRange(selected);
  }
}

方案二:cliboard.js

252.检测设备类型

方案一: ua

  function detectDeviceType() {
  return /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(
    navigator.userAgent
  )
    ? "Mobile"
    : "Desktop";
}
detectDeviceType()

方案二:事件属性

  function detectDeviceType() {
  return ("ontouchstart" in window || navigator.msMaxTouchPoints)
    ? "Mobile"
    : "Desktop";
}
detectDeviceType()

253.Cookie

 function setCookie(key, value, expiredays) {
  var exdate = new Date();
  exdate.setDate(exdate.getDate() + expiredays);
  document.cookie =
    key +
    "=" +
    escape(value) +
    (expiredays == null ? "" : ";expires=" + exdate.toGMTString());
}

  function delCookie(name) {
  var exp = new Date();
  exp.setTime(exp.getTime() - 1);
  var cval = getCookie(name);
  if (cval != null) {
    document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString();
  }
}

  function getCookie(name) {
  var arr,
    reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
  if ((arr = document.cookie.match(reg))) {
    return arr[2];
  } else {
    return null;
  }
}

清空

有时候我们想清空,但是又无法获取到所有的cookie。 这个时候我们可以了利用写满,然后再清空的办法。

日期 Date

254.时间戳转换为时间

 function timestampToTime(timestamp = Date.parse(new Date()), isMs = true) {
  const date = new Date(timestamp * (isMs ? 1 : 1000));
  return `${date.getFullYear()}-${
    date.getMonth() + 1 < 10 ? "0" + (date.getMonth() + 1) : date.getMonth() + 1
  }-${date.getDate()} ${date.getHours()}:${date.getMinutes()}:${date.getSeconds()}`;
}

如果做海外的话,还会有时区问题,一般我用moment解决。如果想看原生的

获取当前时间戳

基于上一个想到的问题

方案一:Date.parse(new Date())

方案二:Date.now()

方案三:+new Date()

文档对象 DOM

255固定滚动条

/**
 * 功能描述:一些业务场景,如弹框出现时,需要禁止页面滚动,这是兼容安卓和 iOS 禁止页面滚动的解决方案
 */

let scrollTop = 0;

function preventScroll() {
  // 存储当前滚动位置
  scrollTop = window.scrollY;

  // 将可滚动区域固定定位,可滚动区域高度为 0 后就不能滚动了
  document.body.style["overflow-y"] = "hidden";
  document.body.style.position = "fixed";
  document.body.style.width = "100%";
  document.body.style.top = -scrollTop + "px";
  // document.body.style['overscroll-behavior'] = 'none'
}

function recoverScroll() {
  document.body.style["overflow-y"] = "auto";
  document.body.style.position = "static";
  // document.querySelector('body').style['overscroll-behavior'] = 'none'

  window.scrollTo(0, scrollTop);
}

256 判断当前位置是否为页面底部

 function bottomVisible() {
  return (
    document.documentElement.clientHeight + window.scrollY >=
    (document.documentElement.scrollHeight ||
      document.documentElement.clientHeight)
  );
}

257判断元素是否在可视范围内

  function elementIsVisibleInViewport(el, partiallyVisible = false) {
  const { top, left, bottom, right } = el.getBoundingClientRect();

  return partiallyVisible
    ? ((top > 0 && top < innerHeight) ||
        (bottom > 0 && bottom < innerHeight)) &&
        ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth))
    : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth;
}

258.获取元素 css 样式

  function getStyle(el, ruleName) {
  return getComputedStyle(el, null).getPropertyValue(ruleName);
}

259.进入全屏

 function launchFullscreen(element) {
  if (element.requestFullscreen) {
    element.requestFullscreen();
  } else if (element.mozRequestFullScreen) {
    element.mozRequestFullScreen();
  } else if (element.msRequestFullscreen) {
    element.msRequestFullscreen();
  } else if (element.webkitRequestFullscreen) {
    element.webkitRequestFullScreen();
  }
}

launchFullscreen(document.documentElement);
launchFullscreen(document.getElementById("id")); //某个元素进入全屏

260退出全屏

function exitFullscreen() {
  if (document.exitFullscreen) {
    document.exitFullscreen();
  } else if (document.msExitFullscreen) {
    document.msExitFullscreen();
  } else if (document.mozCancelFullScreen) {
    document.mozCancelFullScreen();
  } else if (document.webkitExitFullscreen) {
    document.webkitExitFullscreen();
  }
}

exitFullscreen();

261全屏事件

  document.addEventListener("fullscreenchange", function (e) {
  if (document.fullscreenElement) {
    console.log("进入全屏");
  } else {
    console.log("退出全屏");
  }
});

数字 Number

262.数字千分位分割

 function commafy(num) {
  return num.toString().indexOf(".") !== -1
    ? num.toLocaleString()
    : num.toString().replace(/(\d)(?=(?:\d{3})+$)/g, "$1,");
}
commafy(1000)

263.生成随机数

  function randomNum(min, max) {
  switch (arguments.length) {
    case 1:
      return parseInt(Math.random() * min + 1, 10);
    case 2:
      return parseInt(Math.random() * (max - min + 1) + min, 10);
    default:
      return 0;
  }
}
randomNum(1,10)

264 时间戳转时间

/* 时间戳转时间 */
function timestampToTime(cjsj) {
    var date = new Date(cjsj); //时间戳为10位需*1000,时间戳为13位的话不需乘1000
    var Y = date.getFullYear() + '-';
    var M = (date.getMonth() + 1 < 10 ? '0' + (date.getMonth() + 1) : date.getMonth() + 1) + '-';
    var D = (date.getDate() + 1 < 10 ? '0' + (date.getDate()) : date.getDate()) + ' ';
    return Y + M + D
}

265 过滤富文本和空格为纯文本

  /* 过滤富文本和空格为纯文本 */
function filterHtml(str) {
    return str.replace(/<[^<>]+>/g, '').replace(/&nbsp;/ig, '');
}

266 指定显示的文字数量多余的使用省略号代替

 /*指定显示的文字数量多余的使用省略号代替*/
function strEllp(str, num = str.length) {
    var subStr = str.substring(0, num);
    return subStr + (str.length > num ? '...' : '');
}

267 获取滚动条当前的位置

 // 获取滚动条当前的位置
function getScrollTop() {
    var scrollTop = 0
    if (document.documentElement && document.documentElement.scrollTop) {
        scrollTop = document.documentElement.scrollTop;
    } else if (document.body) {
        scrollTop = document.body.scrollTop;
    }
    return scrollTop
}

268 获取当前可视范围的高度

 // 获取当前可视范围的高度
function getClientHeight() {
    var clientHeight = 0
    if (document.body.clientHeight && document.documentElement.clientHeight) {
        clientHeight = Math.min(document.body.clientHeight, document.documentElement.clientHeight)
    } else {
        clientHeight = Math.max(document.body.clientHeight, document.documentElement.clientHeight)
    }
    return clientHeight
}

269 获取文档完整的高度

 // 获取文档完整的高度
function getScrollHeight() {
    return Math.max(document.body.scrollHeight, document.documentElement.scrollHeight)
}
  • partiallyVisible 为是否为完全可见
  • 返回值为 true/false
  • 默认为当前时间转换结果
  • isMs 为时间戳是否为毫秒

a. 补位可以改成 padStart

b. 补位还可以改成 slice

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未经允许不得转载:UI树意境 » 269个JavaScript工具函数 助你提升工作效率(下)

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