269个JavaScript工具函数,助你提升工作效率(下)
原创 叫我詹躲躲 前端技术优选
作者:叫我詹躲躲
原文地址:https://juejin.im/post/5edb6c6be51d4578a2555a9b
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 => ({ '&': '&', '<': '<', '>': '>', "'": ''', '"': '"' }[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 03:03:03console.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。
Math.max
换成Math.min
s>n?s:n
换成s </li> <li>
(n,m)=>m-n换成
(n,m)=>n-m,或者直接取最后一个元素</li> </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
增
function setCookie(key, value, expiredays) { var exdate = new Date(); exdate.setDate(exdate.getDate() + expiredays); document.cookie = key + "=" + escape(value) + (expiredays == null ? "" : ";expires=" + exdate.toGMTString());}
删
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(); }}
查
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(/ /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
补位可以改成 padStart
补位还可以改成 slice