js工具方法

时间替换格式repelace

触发页面resize

var myEvent = new Event('resize');window.dispatchEvent(myEvent);

小数相加

let nums = (a) => {

  if (a != null && a.toString() != "") {

    let r = /^-?(0|[1-9]+\d*|[1-9]+\d*\.\d+|0\.\d+)$/;

    if (r.test(a.toString())) {

      return true;

    }

  }

  return false;

}


let plus = (a, b) => {

  if (!nums(a) || !nums(b)) {

    return null;

  }

  let c, d, m;

  try {

    c = a.toString().split(".")[1].length;

  } catch (e) {

    c = 0;

  }

  try {

    d = b.toString().split(".")[1].length;

  } catch (e) {

    d = 0;

  }

  m = Math.pow(10, Math.max(c, d));

  return (a * m + b * m) / m;

}

小数相减

//减法let minus = (a, b) => {if(!num(a) || !num(b)) {return null;}let c, d, m, n;try {c = a.toString().split(".")[1].length;} catch(e) {c = 0;}try {d = b.toString().split(".")[1].length;} catch(e) {d = 0;}m = Math.pow(10, Math.max(c, d));return(a * m - b * m) / m;// n = (c >= d) ? c : d;// return((a * m - b * m) / m).toFixed(n);//数字转换字符串，保留n位小数}

小数相乘

let multiply = (a, b) => {let m = 0,c = a.toString(),d = b.toString();try {m += c.split(".")[1].length} catch(e) {}try {m += d.split(".")[1].length} catch(e) {}return Number(c.replace(".", "")) * Number(d.replace(".", "")) / Math.pow(10, m)}

相除

let division = (a, b) => {if(!num(a) || !num(b)) {return null;}let c, d, f, g;try {c = a.toString().split(".")[1].length;} catch(e) {c = 0;}try {d = b.toString().split(".")[1].length;} catch(e) {d = 0;}with(Math) {f = Number(a.toString().replace(".", ""));g = Number(b.toString().replace(".", ""));return(f / g) * pow(10, d - c);}}

转码解码

const encode_url  = encodeURIComponent(redirect_uri)// 解码// decodeURIComponent(encode_url)

根据字母排序

const sortList = this.data.openCityList.sort((a, b) => {      const first = a.sort.toUpperCase();      const second = b.sort.toUpperCase();      if (first < second) {          return -1;      }      if (first > second) {          return 1;      }      return 0;    });

是否为刘海屏

checkIsBangScreen(width, height) {  if (width && height) {    // 比 iPhone 8 还长的手机都算刘海屏（简单计算）    return height / width > 667 / 375;  }  // 兜底为“不算作刘海屏”  return false;}

二维数组变一维数组

isEqualObj(obj1, obj2) {  const keys1 = Object.keys(obj1)  const keys2 = Object.keys(obj2)  if (keys1.length !== keys2.length) {    return false  }  return keys1.every(key => obj1[key] === obj2[key])}不相等就添加新数组addPeers(newPeers) {  newPeers.forEach(peer => {    // 保证节点是不能重复的    // 新节点如果不存在就添加    if (!this.peers.find(v => this.isEqualObj(v, peer))) {      this.peers.push(peer)    }  })}

抛出错误

throw 'not valid wallet.json'

指定时间倒计时

countDownNum 倒计时总时间self.props.timeInfo 拿到当前时间后30分钟 倒计时 秒var now = new Date();var time = now.getTime() + 1000*60*30;console.log(new Date(time).getTime())function CountDown () {    timeGap = (self.props.timeInfo - new Date().getTime()) / 1000;    let minutes = Math.floor(timeGap / 60);    let seconds = Math.floor(timeGap % 60);    if (minutes < 10) {        minutes = '0' + minutes;    }    if (seconds < 10) {        seconds = '0' + seconds;    }    let msg = minutes + ':' + seconds;    self.setData({ countDownNum: msg });    --timeGap;    if (timeGap <= 0) {        clearInterval(timer);        self.props.onDeadline();    }}        timer = setInterval(CountDown, 1000);

判断是否在指定区间时间内

@pamse开始时间 @pamse结束时间function func(time1,time2) {      var time = Date.parse( new Date());      var date1 = Date.parse(new Date(time1.replace(/-/g, '/')));      var date2 = Date.parse(new Date(time2.replace(/-/g, '/')));      if (date1 < time && date2 > time) {                  return true;           };            return false;    }

formattingTime = function(str) {  if (typeof str !== 'string') return 'noString';  let newArr = str.split('');  if (!Array.isArray(newArr)) return 'noArray';  newArr.map((item, i) => {    if (item === '-') {      newArr.splice(i, 1, '/')    }  })  return newArr;}获取标准时间var time = "2017-06-23 17:00:00";time = time.replace(/-/g,':').replace(' ',':');time = time.split(':');var time1 = new Date(time[0],(time[1]-1),time[2],time[3],time[4],time[5]);

去掉string前后引号

replace(/['"]+/g, '')

网页顶部距离适配手机透明标题

计算屏幕某个滚动区域的高度，不出滚动条正好是设备的剩余高度移动端

my.getSystemInfo({        success: function(res) {            self.setData({                listHeight: (res.windowHeight * 750 / res.windowWidth  - 657 ) + "rpx"            });        }    })

走马灯

getLeft () {    return Math.abs(parseFloat(this.$container[0].style.marginLeft));  }  /**   * 滚动   */  scroll () {    $('#dollsClone').html($('#dollsList').html());    const $clone = $('#dollsClone')[0];    const self = this;    const offsetLeft = $clone.offsetLeft;    let pos = 10;    this.speed = 100;    this.rolling = () => {      const marginLeft = this.getLeft();      if (marginLeft >= offsetLeft) {        pos = 10;      } else {        pos += 5;      }      self.$container[0].style.marginLeft = `-${pos}px`;    };    this.timer = setInterval(this.rolling, this.speed);  }

截掉开头结尾两个字

得到所有的样式

window.getComputedStyle(div);

是否是一个伪数组

类数组转换为数组、数组的其他方法

var childNodes = nodes[o].childNodes;var s = Array.prototype.slice.call(childNodes);[...childNodes]或者Array.from()

判断一个对象是否为空 是否是函数

JSON.stringify({}) === '{}' ? true : falsefor (x in object) {} 不执行循环就是空a.toString() "[object object]"Object.prototype.toString.call(a) // "[object object]"if (!Object.key(x).length)  返回false就是空typeof a === "function"

 "[object Object]" 从第8位截取到 -1 得到 "Object"  Object.prototype.toString.call(a).slice(8, -1)

得到页面所有标签的种类

去掉字符串前后空格

数组去重

function uniq(array){  var temp = {}, r = [], len = array.length, val, type;  for (var i = 0; i < len; i++) {    val = array[i];    type = typeof val;    if (!temp[val]) {      temp[val] = [type];      r.push(val);    } else if (temp[val].indexOf(type) < 0) {      temp[val].push(type);      r.push(val);    }  }  return r;}

DuplicateRemoval: function (ArrFir, ArrSec) {      console.log('去重操作');      for (var a = 0; a < ArrFir.length; a++) {        for (var b = 0; b < ArrSec.length; b++) {          if (ArrFir[a].id === ArrSec[b].id) {            ArrSec.splice(b, 1);          }        }      }      ArrFir = ArrFir.concat(ArrSec);    }

给数组内对象去重，是属于一类的去掉

util.reducer = function(arr,type) {  if (arr.length == 0) {      return arr;  } else {    if (type) {        var obj = {}        var newArr = arr.reduce((cur,next) => {          console.log(cur)          obj[next.name]? "" : obj[next.name] = true && cur.push(next);          return cur;        },[])        return newArr;    } else {        return Array.from(new Set(arr));    }  }}

数组扁平化

var a = [1,2,3,[4,5,6]]Array.prototype.concat.apply([], a)

递归、阶乘

 获取滚动条当前的位置/使用滚动条

onScroll: function (DOMID) {Z('#' + DOMID).scroll(() => {console.log(document.getElementById(DOMID).scrollHeight + ':scrollHeight' + ' ' + DOMID);// 内容可视区域的高度加上溢出（滚动）的距离。console.log(document.getElementById(DOMID).clientHeight + ':clientHeight' + ' ' + DOMID);// 内容可视区域console.log(document.getElementById(DOMID).scrollTop + ':scrollTop' + ' ' + DOMID); // 滚动距离var clientHeight = document.getElementById(DOMID).clientHeight;var scrollHeight = document.getElementById(DOMID).scrollHeight;var scrollTop = document.getElementById(DOMID).scrollTop;if (scrollTop + 100 + clientHeight >= scrollHeight) {console.log('到底部了，需要加载');this._loadMore();}});},setTimeout(() => window.scroll(0, 875), 0)

拿到随机的一组文案

getZhiContent () {let result = {preContent: '小伙伴们，给大家发红包喽！人人可领，天天可领，领完就能用。祝大家领取的红包金额大大大！#吱口令#长按复制此消息，打开支付宝就能领取！',endContent: '',channel: ''};const list = window.__config.zhiContentList;if (list.length) {const index = Math.round(Math.random() * (list.length - 1));const content = list[index].text.split('#token#');let channel;list[index].channel && (channel = '_' + list[index].channel);result.preContent = content[0] || result.preContent;result.endContent = content[1] || '';result.channel = channel;}return result;}

页面加载状态改变时

let mySwiper;document.onreadystatechange = loadingChange;//当页面加载状态改变的时候执行这个方法.function loadingChange() {// $("#btn").trigger("click");if(document.readyState == "complete"){ //当页面加载状态为完全结束时进入// alert(1)}}  

禁止用户多次点击

<script>$(document).ready(function(){    $("#submit").click(function(){      var nowTime = new Date().getTime();    var clickTime = $(this).attr("ctime");    if( clickTime != 'undefined' && (nowTime - clickTime < 5000)){        alert('操作过于频繁，稍后再试');        return false;     }else{        $(this).attr("ctime",nowTime);        alert('提交成功');     }          }); });</script>

是不是整数

去除一个数的小数部分

禁止页面拖动

// 禁止页面拖动let node = document.querySelector('.index-frame');node.addEventListener('touchmove', function (e) {  e.preventDefault();}, false);

千位分隔符

function numFormat(num){    num=num.toString().split(".");  // 分隔小数点    var arr=num[0].split("").reverse();  // 转换成字符数组并且倒序排列    var res=[];    for(var i=0,len=arr.length;i<len;i++){      if(i%3===0&&i!==0){         res.push(",");   // 添加分隔符      }      res.push(arr[i]);    }    res.reverse(); // 再次倒序成为正确的顺序    if(num[1]){  // 如果有小数的话添加小数部分      res=res.join("").concat("."+num[1]);    }else{      res=res.join("");    }    return res;}

节流防抖

// 简单的节流函数function throttle(func, wait, mustRun) {	var timeout,		startTime = new Date(); 	return function() {		var context = this,			args = arguments,			curTime = new Date(); 		clearTimeout(timeout);		// 如果达到了规定的触发时间间隔，触发 handler		if(curTime - startTime >= mustRun){			func.apply(context,args);			startTime = curTime;		// 没达到触发间隔，重新设定定时器		}else{			timeout = setTimeout(func, wait);		}	};};// 实际想绑定在 scroll 事件上的 handlerfunction realFunc(){	console.log("Success");}// 采用了节流函数window.addEventListener('scroll',throttle(realFunc,500,1000));例子2function debounce(fn, wait) {  var timeout;  return function() {    var ctx = this, args = arguments;    clearTimeout(timeout);    timeout = setTimeout(function() {      fn.apply(ctx, args);    }, wait);  };}vue 防抖3export const debounce = (fn, delay = 500) => {  let timer;  return function() {    let args = arguments;    if(timer) {      clearTimeout(timer);    }    timer = setTimeout(() => {      fn.apply(this, args);    }, delay);  };}methods内写方法名字 ： 防抖函数 传入thiscommitDialog: debounce((dialogTitle, self) => {

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