各种函数收集，持续更新~

1. 数组对象去重

使用reduce,自己看着改

let arr = [{id: 1, name: '周瑜'},{id: 3, name: '王昭君'},{id: 2, name: '亚瑟'},{id: 1, name: '小乔'},{id: 2, name: '大桥'},{id: 3, name: '韩信'}
];
let obj = {}
arr = arr.reduce((preVal,curVal) => {obj[curVal.id] ? "" : obj[curVal.id] = preVal.push(curVal)return preVal},[])
console.log(arr)

2. 时间转换函数

第一个参数是输入的时间，标准格式或时间戳格式都可

第二个参数是输出的样子，要啥写啥样，全部是这样 ‘yyyy-MM-dd hh:mm:ss’

export function formatDate(t, format='yyyy-MM-dd') {if(t==''||t<=0||t==null||t=='null'){return '';}if(typeof t == 'string'){t = t.replace(new RegExp(/-/gm) ,"/");}const d = new Date(t);const o = {"M+" : d.getMonth() + 1,// month"d+" : d.getDate(),// day"h+" : d.getHours(),// hour"m+" : d.getMinutes(),// minute"s+" : d.getSeconds(),// second"q+" : Math.floor((d.getMonth() + 3) / 3),// quarter"S" : d.getMilliseconds()// millisecond};if (/(y+)/.test(format) || /(Y+)/.test(format)) {format = format.replace(RegExp.$1, (d.getFullYear() + "").substr(4 - RegExp.$1.length));}for ( let k in o) {if (new RegExp("(" + k + ")").test(format)) {format = format.replace(RegExp.$1, RegExp.$1.length == 1 ? o[k]: ("00" + o[k]).substr(("" + o[k]).length));}}return format;
}

获取当前时间的上个月

export function getLastMonth() {//获取上个月日期const date = new Date();let year = date.getFullYear();let month = date.getMonth();if (month == 0) {year = year - 1;month = 12;}month = (month + "").length == 1 ? "0" + month : monthreturn year + "-" + month;
}

3. 深拷贝

export function deepClone(source) {if (!source && typeof source !== 'object') {throw new Error('error arguments', 'deepClone')}const targetObj = source.constructor === Array ? [] : {}Object.keys(source).forEach(keys => {if (source[keys] && typeof source[keys] === 'object') {targetObj[keys] = deepClone(source[keys])} else {targetObj[keys] = source[keys]}})return targetObj
}

4. js精度问题解决（加减乘除）

加

export function accAdd(arg1, arg2) {let r1, r2, m, c;try {r1 = arg1.toString().split(".")[1].length;}catch (e) {r1 = 0;}try {r2 = arg2.toString().split(".")[1].length;}catch (e) {r2 = 0;}c = Math.abs(r1 - r2);m = Math.pow(10, Math.max(r1, r2));if (c > 0) {const cm = Math.pow(10, c);if (r1 > r2) {arg1 = Number(arg1.toString().replace(".", ""));arg2 = Number(arg2.toString().replace(".", "")) * cm;} else {arg1 = Number(arg1.toString().replace(".", "")) * cm;arg2 = Number(arg2.toString().replace(".", ""));}} else {arg1 = Number(arg1.toString().replace(".", ""));arg2 = Number(arg2.toString().replace(".", ""));}return (arg1 + arg2) / m;
}

减

跟上面加法配合用

export function accSub(arg1, arg2) {return accAdd(arg1, -arg2);
}

乘

export function accMul(arg1,arg2) {let m=0,s1=arg1.toString(),s2=arg2.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);
}

除

export function accDiv(arg1, arg2) {let t1 = 0, t2 = 0, r1, r2;try {t1 = arg1.toString().split(".")[1].length;} catch (e) {}try {t2 = arg2.toString().split(".")[1].length;} catch (e) {}r1 = Number(arg1.toString().replace(".", ""));r2 = Number(arg2.toString().replace(".", ""));return (r1 / r2) * Math.pow(10, t2 - t1);
}

5. toFiexed函数重写

重写原因：toFixed的四舍五入规则有问题，是四舍六入五成双，解决办法重写

Number.prototype.toFixed = function (n) {if (n > 20 || n < 0) {throw new RangeError('toFixed() digits argument must be between 0 and 20');}const number = this;if (isNaN(number) || number >= Math.pow(10, 21)) {return number.toString();}if (typeof (n) == 'undefined' || n == 0) {return (Math.round(number)).toString();}// 判断是正数还是负数let isPositive = true;if(parseFloat(number)<0){isPositive = false;}let result = number.toString();// 增加判断科学计数法的支持（只处理绝对值小于1的小数科学技术法）if(result.indexOf("e")>0&&Math.abs(number)<1){result =  scienceToString(number);}const arr = result.split('.');// 整数的情况if (arr.length < 2) {result += '.';for (let i = 0; i < n; i += 1) {result += '0';}return result;}const integer = arr[0];const decimal = arr[1];if (decimal.length == n) {return result;}if (decimal.length < n) {for (let i = 0; i < n - decimal.length; i += 1) {result += '0';}return result;}result = integer + '.' + decimal.substr(0, n);const last = decimal.substr(n, 1);// 四舍五入，转换为整数再处理，避免浮点数精度的损失if (parseInt(last, 10) >= 5) {const x = Math.pow(10, n);if(isPositive){result = (Math.round((parseFloat(result) * x)) + 1) / x;} else {result = (Math.round((parseFloat(result) * x)) - 1) / x;}result = result.toFixed(n);}return result;
};

6.手机号校验与隐藏手机号中间4位

//这个函数是先判断传入的是否是手机号function isMobile(mobileNumber){var reg = /^((1[3456789]{1}[0-9]{1})+\d{8})$/;// var reg = /^[1][3,4,5,7,8][0-9]{9}$/;return reg.test(mobileNumber);
}
//然后再隐藏手机号中间4位function hideMobile(mobileNumber, mode) {if(mode == 'visible'){return mobileNumber;}if(!mobileNumber){return '';}//判断非空if(isMobile(mobileNumber)){//判断是否是手机号var reg = /^(\d{3})\d{4}(\d{4})$/;//手机加密return mobileNumber.replace(reg, "$1****$2");}else{if(mobileNumber.length>=7){//固话加密return mobileNumber.substr(0,mobileNumber.length-2)+"**";}return mobileNumber;}
}

7. 身份证号校验与加密+校验位检测+15位转18位身份证

//身份证号加密
export function hideIdCard(idCardNumber, mode) {if(mode == 'visible'){return idCardNumber;}if(!idCardNumber){return '';}//判断非空if(checkCertificateNo(idCardNumber)){//判断是否是身份证号return idCardNumber.substring(0,3)+"****";   //身份证加密}
}
//身份证号的验证
export function checkCertificateNo(num) {let len = num.length, re;if (len == 15)re = new RegExp(/^([0-9]{6})()?([0-9]{2})([0-9]{2})([0-9]{2})([0-9]{3})$/);else if (len == 18)re = new RegExp(/^([0-9]{6})()?([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{3})([0-9Xx])$/);else {//alert("请输入15或18位身份证号,您输入的是 "+len+ "位");return false;}let a = num.match(re);if (a != null) {if (len == 15) {var D = new Date("19" + a[3] + "/" + a[4] + "/" + a[5]);var B = D.getYear() == a[3] && (D.getMonth() + 1) == a[4] && D.getDate() == a[5];} else {var D = new Date(a[3] + "/" + a[4] + "/" + a[5]);var B = D.getFullYear() == a[3] && (D.getMonth() + 1) == a[4] && D.getDate() == a[5];}if (!B) {//alert("输入的身份证号 "+ a[0] +" 里出生日期不对！");return false;}} else {return false;}// 验证最后一位的校验位if(checkParity(num) === false){return false;}return true;
}//校验位的检测
const checkParity = function(obj)
{//15位转18位obj = changeFivteenToEighteen(obj);var len = obj.length;if(len == '18'){var arrInt = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];var arrCh = ['1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'];var cardTemp = 0, i, valnum;for(i = 0; i < 17; i ++){cardTemp += obj.substr(i, 1) * arrInt[i];}valnum = arrCh[cardTemp % 11];if (valnum == obj.substr(17, 1)){return true;}return false;}return false;
};//15位转18位身份证号
const changeFivteenToEighteen = function(obj)
{if(obj.length == '15'){var arrInt = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];var arrCh = ['1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'];var cardTemp = 0, i;obj = obj.substr(0, 6) + '19' + obj.substr(6, obj.length - 6);for(i = 0; i < 17; i ++){cardTemp += obj.substr(i, 1) * arrInt[i];}obj += arrCh[cardTemp % 11];return obj;}return obj;
};

8. 千位符格式化（123,456）

export function milliFormat(num) {return num && num.toString().replace(/\d+/, function(s){return s.replace(/(\d)(?=(\d{3})+$)/g, '$1,')})
}

千位符格式化且可以保留两位小数

export function formatter(number) {if(number) {return String(number).replace(/\B(?=(\d{3})+(?!\d))/g, ',')} else {return '0.00'}
}