// 精度丢失异常数据汇总
10.3950 * 3935.00 = 期望40904.33， 异常结果40904.32
7.3950 * 3835.00 = 期望28359.83， 异常结果28359.82
11.777 * 4215 = 期望49640.06， 异常结果49640.05
12.445 * 4005 = 期望49842.23，异常结果49842.22
3721*17.0480 = 期望63435.61，异常结果63435.60
3621*5.0060 = 期望18126.73，异常结果18126.72
vue项目中直接装插件
npm install bignumber.js
import {
BigNumber } from 'bignumber.js';
// +
export function add(a, b) {
a = BigNumber(a);
b = BigNumber(b);
return a.plus(b).toNumber(); //结果需要用toNumber转为普通数字
}
// -
export function minus(a, b) {
a = BigNumber(a);
b = BigNumber(b);
return a.minus(b).toNumber();
}
// *
export function mut(a, b) {
a = BigNumber(a);
b = BigNumber(b);
return a.multipliedBy(b).toNumber();
}
// /
export function dev(a, b) {
a = BigNumber(a);
b = BigNumber(b);
return a.dividedBy(b).toNumber();
}
界面中使用：
import {
add,
minus,
mut,
dev
} from '@/utils/common.js' //公共方法
row.amountStr = (this.mut(Number(row.salePriceStr), Number(row.weightStr))).toFixed(2)
toFixed也有精度丢失问题，直接main.js中改写toFixed方法
Number.prototype.toFixed = function(d) {
var s = this + ''
if (!d) d = 0
if (s.indexOf('.') === -1) s += '.'
s += new Array(d + 1).join('0')
if (new RegExp('^(-|\\+)?(\\d+(\\.\\d{0,' + (d + 1) + '})?)\\d*$').test(s)) {
let s = '0' + RegExp.$2; var pm = RegExp.$1; var a = RegExp.$3.length; var b = true
if (a === d + 2) {
a = s.match(/\d/g)
if (parseInt(a[a.length - 1]) > 4) {
for (var i = a.length - 2; i >= 0; i--) {
a[i] = parseInt(a[i]) + 1
if (a[i] === 10) {
a[i] = 0
b = i !== 1
} else break
}
}
s = a.join('').replace(new RegExp('(\\d+)(\\d{' + d + '})\\d$'), '$1.$2')
}
if (b) s = s.substr(1)
return (pm + s).replace(/\.$/, '')
}
return this + ''
}
如果vue3中遇到精度丢失问题，可以创建一个fixed.js文件
// // js
if (!Number.prototype._toFixed) {
// eslint-disable-next-line no-extend-native
Number.prototype._toFixed = Number.prototype.toFixed
}
// eslint-disable-next-line no-extend-native
Number.prototype.toFixed = function (d) {
let s = this + ''
if (!d) {
d = 0
}
if (s.indexOf('.') === -1) {
s += '.'
}
s += new Array(d + 1).join('0')
if (new RegExp('^(-|\\+)?(\\d+(\\.\\d{0,' + (d + 1) + '})?)\\d*$').test(s)) {
let s = '0' + RegExp.$2
let pm = RegExp.$1
let a = RegExp.$3.length
let b = true
if (a === d + 2) {
a = s.match(/\d/g)
if (parseInt(a[a.length - 1]) > 4) {
for (let i = a.length - 2; i >= 0; i--) {
a[i] = parseInt(a[i]) + 1
if (a[i] === 10) {
a[i] = 0
b = i !== 1
} else {
break
}
}
}
s = a.join('').replace(new RegExp('(\\d+)(\\d{' + d + '})\\d$'), '$1.$2')
}
if (b) {
s = s.substr(1)
}
return (pm + s).replace(/\.$/, '')
}
return this + ''
}
然后再main.ts文件中引入即可
import '@/utils/fixed'
方式二： 封装js方法
// 乘法
function highPrecisionMul(data1, data2) {
let m = 0;
const s1 = data1.toString();
const s2 = data2.toString();
// 获取所有参数小数位长度之和
try {
m += s1.split(".")[1].length;
} catch (e) {
e => e }
try {
m += s2.split(".")[1].length;
} catch (e) {
e => e }
// 替换掉小数点转为数字相乘再除以10的次幂值
return (
(Number(s1.replace(".", "")) * Number(s2.replace(".", ""))) /
Math.pow(10, m)
);
};
// 加法
function highPrecisionAdd(data1, data2) {
let r1, r2;
// 获取每个参数的小数的位数
try {
r1 = data1.toString().split(".")[1].length;
} catch (e) {
r1 = 0;
}
try {
r2 = data2.toString().split(".")[1].length;
} catch (e) {
r2 = 0;
}
// 计算底数为10以最大小数位数为次幂的值
const m = Math.pow(10, Math.max(r1, r2));
// 把所有参数转为整数后相加再除以次幂的值
return (data1 * m + data2 * m) / m;
};
// toFixed精度问题 重写
function toSuperFixed(n, d) {
var s = n + "";
if (!d) d = 0;
if (s.indexOf(".") === -1) s += ".";
s += new Array(d + 1).join("0");
if (new RegExp("^(-|\\+)?(\\d+(\\.\\d{0," + (d + 1) + "})?)\\d*$").test(s)) {
let s = "0" + RegExp.$2; var pm = RegExp.$1; var a = RegExp.$3.length; var b = true;
if (a === d + 2) {
a = s.match(/\d/g);
if (parseInt(a[a.length - 1]) > 4) {
for (var i = a.length - 2; i >= 0; i--) {
a[i] = parseInt(a[i]) + 1;
if (a[i] === 10) {
a[i] = 0;
b = i !== 1;
} else break;
}
}
s = a.join("").replace(new RegExp("(\\d+)(\\d{" + d + "})\\d$"), "$1.$2");
}
if (b) s = s.substr(1);
return (pm + s).replace(/\.$/, "");
}
return this + "";
}
使用：
this.toSuperFixed(this.highPrecisionMul(Number(row.priceStr), Number(row.weightStr)), 2)
