驼峰字符串转下划线_01

function decamelize(string, options) {
    options = options || {};
    var separator = options.separator || '_';
    var split = options.split || /(?=[A-Z])/;

    return string.split(split).join(separator).toLowerCase();
};
console.log(decamelize("sellerCnt"));    //seller_cnt
console.log(decamelize("minPriceOne"));  //min_price_one

console.log(decamelize("sellerCnt", { separator: '-' }));   // seller-cnt
console.log(decamelize("minPriceOne", { separator: '-' })); // min-price-one

驼峰字符串转下划线_02

function underline(str){
  return str.replace(/\B([A-Z])/g, '_$1').toLowerCase()
}

underline('isPhone') // is_phone

验证手机号

isPhone: function(num) {
    var reg = /^1[3456789]\d{9}$/;
    return reg.test(num);
  }

验证邮箱

isEmail: function(num) {
    var reg = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/;
    return reg.test(num);
  }

验证手机号或者邮箱

isPhoneEmail:function (num) {
    var reg = /(^1[3456789]\d{9}$)|(^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$)/
    return reg.test(num);
  }

验证身份证号码

isNumberId: function(num) {
    // 身份证号码为15位或者18位，15位时全为数字，18位前17位为数字，最后一位是校验位，可能为数字或字符X
    var reg = /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/;
    return reg.test(num);
  }

将时间戳转换成指定的日期格式

formatDate: function(x, y) {
    if (!(x instanceof Date)) {
      var date = new Date();
      date.setTime(x * 1000);
      x = date;
    }
    var z = {
      y: x.getFullYear(),
      M: x.getMonth() + 1,
      d: x.getDate(),
      h: x.getHours(),
      m: x.getMinutes(),
      s: x.getSeconds()
    };
    return y.replace(/(y+|M+|d+|h+|m+|s+)/g, function(v) {
      return ((v.length > 1 ? "0" : "") + eval("z." + v.slice(-1))).slice(
        -(v.length > 2 ? v.length : 2)
      );
    });
  }

将日期格式转换成时间戳

timeStamp:function (myDate) {
    var date = new Date(myDate);
    return date.getTime()/1000;
  }

传入截止时间的方式，进行倒计时

leftTimer(enddate) {
    let leftTime = (new Date(enddate)) - new Date(); //计算剩余的毫秒数
    let days = parseInt(leftTime / 1000 / 60 / 60 / 24, 10); //计算剩余的天数
    let hours = parseInt(leftTime / 1000 / 60 / 60 % 24, 10); //计算剩余的小时
    let minutes = parseInt(leftTime / 1000 / 60 % 60, 10); //计算剩余的分钟
    let seconds = parseInt(leftTime / 1000 % 60, 10); //计算剩余的秒数
    days = this.checkTime(days);
    hours = this.checkTime(hours);
    minutes = this.checkTime(minutes);
    seconds = this.checkTime(seconds);
    if (days <= '00' && hours <= '00' && minutes <= '00' && seconds <= '00') {
      return null;
    }
    if (days >= '00' || hours >= '00' || minutes >= '00' || seconds >= '00') {
      return minutes + ":" + seconds
    }
  }

超简洁的js倒计时方法

const countDown = (second) => {
  const s = second % 60;
  const m = Math.floor(second / 60);

  return `${`00${m}`.slice(-2)} : ${`00${s}`.slice(-2)}`;
};

let time = 5 * 60;  // 5分钟

const timer = setInterval(() => {
  const show = countDown(time--);
  console.log(show);
  if(time < 0) {
    console.log('倒计时结束！');
    clearInterval(timer);
  }
}, 1000);

获取N天前的日期

getNday(n) {
    let date = new Date();
    let newDate = new Date(date.getTime() - n * 24 * 60 * 60 * 1000);
    let time = newDate.getFullYear() + "-" + (newDate.getMonth() + 1) + "-" + newDate.getDate();
    return time;
  }

是否是微信环境

inWeixin: function() {
    var ua = navigator.userAgent.toLowerCase();
    return ua.indexOf("micromessenger") != -1;
  }

获取cookie

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

设置cookie

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

删除指定cookie

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

删除所有cookie

deleteCookie: function() {
    var keys = document.cookie.match(/[^ =;]+(?=\=)/g);
    if (keys) {
      for (var i = keys.length; i--; )
        document.cookie = keys[i] + "=0;expires=" + new Date(0).toUTCString() + ";domain=" + document.domain + ";path=/";
    }
  }

获取url参数

GetQueryString: function(name) {
    var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
    var r = window.location.search.substr(1).match(reg);
    if (r != null) return unescape(r[2]);
    return null;
  }

拼接对象为请求字符串

/**
   * 拼接对象为请求字符串
   * @param {Object} obj - 待拼接的对象
   * @returns {string} - 拼接成的请求字符串
   *
   * 代码中使用的方式 es6语法:
   * @param {string} baseUrl - url地址
   * var finalUrl = `${baseUrl}?${encodeParams(obj)}`;
   */
  encodeParams: function(obj) {
    var params = [];
    Object.keys(obj).forEach(function(key) {
      var value = obj[key];
      // 如果值为undefined我们将其置空
      if (typeof value === "undefined") {
        value = "";
      }
      if (typeof value === "object") {
        value = JSON.stringify(value);
      }
      // 对于需要编码的文本（比如说中文）我们要进行编码
      params.push([key, encodeURIComponent(value)].join("="));
    });
    return params.join("&");
  }

获取url中”?”符后的字符串并转化为对象

GetRequest: function() {
    var url = location.search;
    var theRequest = new Object();
    if (url.indexOf("?") != -1) {
      var str = url.substr(1);
      strs = str.split("&");
      for (var i = 0; i < strs.length; i++) {
        theRequest[strs[i].split("=")[0]] = unescape(strs[i].split("=")[1]);
      }
    }
    return theRequest;
  }

保留n位小数,不会进行四舍五入

toDecimal:function (cnum,cindex) {
    let value = String(cnum);
    if (value.indexOf(".") > 0) {
      var left = value.substr(0, value.indexOf("."));
      var right = value.substr(value.indexOf(".") + 1, value.length);
      if (right.length > cindex) {
        right = right.substr(0, cindex);
      }
      value = left + "." + right;
      return value;
    }else {
      return cnum;
    }
  }

科学计数法

science: function (num) {
    if ((num + '').indexOf('E-') > -1 || (num + '').indexOf('e-') > -1) {
      var a = (num + '').indexOf('E-') > -1 ? (num + '').split('E-') : (num + '').split('e-'),
        b = a[0],
        c = parseInt(a[1]),
        d = [],
        i;
      for (i = 0; i < c - 1; i++) {
        d[i] = 0;
      }
      num = '0.' + d.join('') + (b * 100);
    }
    return num
  }

eg: science(1.2000002203998405e-10) // 0.000000000120.00002203998406

保留n位小数（不进行四舍五入）

toDecimal:function (cnum,cindex) {
    let value = String(cnum);
    if (value.indexOf(".") > 0) {
      var left = value.substr(0, value.indexOf("."));
      var right = value.substr(value.indexOf(".") + 1, value.length);
      if (right.length > cindex) {
        right = right.substr(0, cindex);
      }
      value = left + "." + right;
      return value;
    }else {
      return cnum;
    }
  }

数数相加，避免浮点数

addNum(num1,num2){
    let sq1,sq2,m;
    try{
      sq1 = num1.toString().split('.')[1].length;
    }
    catch(e){
      sq1 = 0;
    }
    try{
      sq2 = num2.toString().split('.')[1].length;
    }
    catch(e){
      sq2 = 0;
    }
    m = Math.pow(10,Math.max(sq1,sq2));
    return (Math.round(num1*m) + Math.round(num2*m)) / m;
  }

获取小数点位数

decimalLength(num){
    return String(num).length - (String(num).indexOf('.') + 1);
  }

去除数组中的空元素

filter_array(array) {
    return array.filter(item => item);
  }

数组对象排序 大到小 eg:arr.sort(maxSort(“age”)) //根据key = “age” 做排序

maxSort:function (prop) {
    return function (obj1, obj2) {
      var val1 = obj1[prop];
      var val2 = obj2[prop];
      if (!isNaN(Number(val1)) && !isNaN(Number(val2))) {
        val1 = Number(val1);
        val2 = Number(val2);
      }
      if (val1 > val2) {
        return -1;
      } else if (val1 < val2) {
        return 1;
      } else {
        return 0;
      }
    } 
  }

数组对象排序 小到大 eg:arr.sort(minSort(“age”))//根据key = “age” 做排序

minSort:function (prop) {
    return function (obj1, obj2) {
      var val1 = obj1[prop];
      var val2 = obj2[prop];
      if (!isNaN(Number(val1)) && !isNaN(Number(val2))) {
        val1 = Number(val1);
        val2 = Number(val2);
      }
      if (val1 < val2) {
        return -1;
      } else if (val1 > val2) {
        return 1;
      } else {
        return 0;
      }
    } 
  }

格林尼治时间字符串转时间字符串

formatDateGL(myTimes){
    let d = new Date(myTimes);
    let format =  d.getFullYear() + '-' + (d.getMonth() + 1) + '-' + d.getDate() + ' ' + d.getHours() + ':' + 
   d.getMinutes() + ':' + d.getSeconds(); 
    return this.timeStamp(format)
}

数字千分位格式化

comdify(num) {
    return num.toString().replace(/\d+/, function (n) { // 先提取整数部分
      return n.replace(/(\d)(?=(\d{3})+$)/g, function ($1) { // 对整数部分添加分隔符
          return $1 + ",";
      });
    });
  }

过滤字符串中的符号

filterTrim(str){
    return str.replace(/[^a-z0-9]+/ig,"");
  }

将base64的图片转为Blob格式

dataURLtoBlob(dataurl) {
    var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
    while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], { type: mime });
  }

将base64图片转file文件

dataURLtoFile(dataurl, filename) {
    var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
    bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
    while(n--){
      u8arr[n] = bstr.charCodeAt(n);
    }
    return new File([u8arr], filename, {type:mime});
  }

复制功能（iOS下某些版本不兼容）

Copy(copyInfo){
    return new Promise((resolve, reject) => {
      let copyUrl = document.createElement("input");//创建一个input框获取需要复制的文本内容
      copyUrl.value = copyInfo;
      let appDiv = document.getElementById('app');
      appDiv.appendChild(copyUrl); 
      copyUrl.select();
      document.execCommand("Copy");
      copyUrl.remove()
      resolve(true);
    })
  }

随机生成uuid

generateUUID() {
    var d = new Date().getTime();
    if (window.performance && typeof window.performance.now === "function") {
        d += performance.now(); //use high-precision timer if available
    }
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
        var r = (d + Math.random() * 16) % 16 | 0;
        d = Math.floor(d / 16);
        return (c == 'x' ? r : (r & 0x3 | 0x8)).toString(16);
    });
    return uuid;
  }