一些常用的函数

js实现LazyMan

Lazyman.js

js封装ajax,jsonp

Ajax.js

js双向绑定

doublebinding.js

js十种排序算法

Sort.md

返回带逗号的数字

functionnumberWithCommas(x){returnx.toString().replace(/\B(?=(\d{3})+(?!\d))/g,',')}

是否是数组

functionisArray(arr){returntypeofArray.isArray==='function' ?
Array.isArray(arr) : Object.prototype.toString.call(arr)==='[Object Array]'}

数组去重

Array.prototype.unique=function(){return[...newSet(this)]}

functionunique(arr){lettempArr=[]arr.map((v)=>{if(!(vintempArr)){tempArr[tempArr.length]=v}})returntempArr}

Array.prototype.unique=function(){letres=this.sort(),returnres.filter((v,i,context)=>{returnv!==context[i+1]})}

获取随机颜色值

functiongetRandomColor(){letcolor='#',letters='0123456789abcdef'for(leti=0;i<6;i++){color+=letters[Math.round(Math.random()*letters.length)]}returncolor}

functionrandomColor(){letcolor='rgba('for(i=0;i<3;i++){color+=`${Math.round(Math.random()*255)},`}returncolor+=`${Math.random().toFixed(1)})`}

hexToRgb

functionhexToRgb(hex){constresult=/^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex)return!!result ? {r: parseInt(result[1],16),g: parseInt(result[2],16),b: parseInt(result[3],16),} : null}

数组乱序

functionshuffle(arr){for(leti=arr.length;i;i--){letj=Math.floor(Math.random()*i);[arr[i-1],arr[j]]=[arr[j],arr[i-1]];//ES6解构赋值}}

[1,2,3,4,5].sort(()=>{returnMath.random()>.5 ? 1 : -1})

functionshuffle(arr){letrandom=0,result=[],origin=[]arr.map(item=>{origin.push(item)})while(arr.length>0){random=Math.floor(Math.random()*arr.length)//生产原数组随机索引result.push(arr[random])//向结果数组添加元素arr.splice(random,1)//删除原数组元素}return{
result,
origin
}}

数字求和

functionforSum(n){if(typeofn!=='number'){return}letsum=0for(n;n>=1;n--){sum+=n}returnsum}

函数柯里化

functionsum(item){varcur=item;varinner=function(next){returnnext==null ? cur : (cur+=next,inner)};returnitem==null ? undefined : inner}

冒泡排序

functionbubbleSort(arr){constlen=arr.lengthfor(leti=0;i<len;i++){for(letj=0;j<len-1;j++){if(arr[j]>arr[j+1]){[arr[j],arr[j+1]]=[arr[j+1],arr[j]]}}}returnarr}

对象深拷贝

functiondeepCopy(parent,child){child=child||{}if(typeofparent!=='object'){return}for(letiteminparent){if(parent.hasOwnProperty(item)){if(typeofparent[item]==='object'){child[item]=Array.isArray(parent[item])? [] : {}deepCopy(parent[item],child[item])}else{child[item]=parent[item]}}}returnchild}

constcopy=JSON.parse(JSON.stringify(source))

变量交换

functionchange(a,b){return[a,b]=[b,a]}

寻找数组中最大值与最小值得差值

functiondiff(arr){returnMath.max(...arr)-Math.min(...arr)}

获取n天前/后的日期

functiongetDayBeforeAfter(date,type,days){date=date||newDate()type=type||'after'days=days||1if(!(dateinstanceofDate)){if(date.indexOf('-')!=-1){date.replace(/\-/g,'/')}date=newDate(date)}letnewDate=dateswitch(type){case"after":
newDate=newDate(date.getTime()+(days*24*60*60*1000))breakcase"before":
newDate=newDate(date.getTime()-(days*24*60*60*1000))break}return`${newDate.getFullYear()}/`+`${newDate.getMonth()+1}/`+`${newDate.getDate()}`}

使用Promise对象处理ajax请求

functionpromiseAjax(url){returnnewPromise(function(resolve,reject){constxhr=newXMLHttpRequest()xhr.open('GET',url,true)xhr.onload=function(){if(xhr.status>=200&&xhr.status<400){letdata=JSON.parse(xhr.responseText)resovle(data)}else{reject(newError(xhr.statusText))}}xhr.onerror=function(){reject(newError(xhr.statusText))}xhr.send()})}letURL='http://news-at.zhihu.com/api/4/news/latest'promiseAjax(URL).then(function(data){console.log(data)}).catch(function(err){console.log(err)})

Fetch API

consturl=URL.fomat({pathname:''})constheaders=newHeaders({'Content-type':'application/json'})constrequest=newRequest(url,{method:'get',mode:'cors',credentials:'include',
headers,body:JSON.stringify(body)})constreponse=awaitfetch(request)constdata=awaitreponse.json()

字符串重复

String.prototype.repeatify=String.prototype.repeatify||function(n){if(typeofn!=='number')returnletstr=''for(leti=0;i<n;i++){str+=this}returnstr}

数字左补全

functionleftPad(num){letn=parseInt(num,10)returnn>0 ? (n<=9 ? '0'+n : n) : '00'}

斐波那契数列

functionfibonacci(n){constres=[1,1]if(typeofn!=='number')returnif(n===0)returnreswhile(n>0){res.push(res[res.length-2]+res[res.length-1])n--}returnres}

阶乘

functionfactorial(n){functionfact(n,res){if(n<2)returnresreturnfact(n-1,n*res)}returnfact(n,1)}

生成随机字符串

functiongetRandomString(n){if(typeofn!='number')returnletstr=""for(;str.length<n;str+=Math.random().toString(36).substr(2)){}returnstr.substr(0,n)}

将浮点数左边的数每3位加逗号

functioncommafy(num){returnnum&&num.toString().replace(/(\d)(?=(\d{3})+\.)/g,($1,$2)=>{return$2+=','})}

函数防抖

functiondebounce(fn,delay){lettimer=nullreturnfunction(){constself=thisletargs=argumentsclearTimeout(timer)timer=setTimeout(()=>{fn.apply(self,args)},delay)}}

实现indexOf

Array.prototype.indexOf=Array.prototype.indexOf||function(ele,fromIndex){if(this===null||!ele){return-1}letlength=this.lengthleti=fromIndex||0letcur=-1while(true){if(this[i]===ele){cur=ibreak}else{i++if(length===i){break}continue}}returncur}