【函数】各种函数收集，持续更新~

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)

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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;
}
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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 : month
    return year + "-" + month;
}
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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
}
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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;
}
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减

跟上面加法配合用

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

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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);
}
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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);
}
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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;
};
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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;
    }
}
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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;
};
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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,')
        })
}
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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'
	}
}
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