前端实现获取两位小数(toFixed(num))

最新推荐文章于 2025-06-10 12:19:00 发布

原创最新推荐文章于 2025-06-10 12:19:00 发布 · 1.2k 阅读

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CC 4.0 BY-SA版权

文章标签：

#java #js #javascript

本文介绍了一个用于高精度算术运算的bigDecimal.js库，其中包括加、减、乘、除四种基本运算，并详细展示了如何使用这些方法来处理浮点数的计算问题，确保计算结果的准确性。

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toFixed(num)方法可把 Number 四舍五入为指定小数位数的数字。
num :规定小数的位数，是 0 ~ 20 之间的值，包括 0 和 20，有些实现可以支持更大的数值范围。如果省略了该参数，将用 0 代替。
bigDecimal.js:

const bigDecimal = function() {
    //加
    function add(arg1,arg2){
        var r1,r2,m;
        try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
        try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
        m=Math.pow(10,Math.max(r1,r2));
        return (arg1*m+arg2*m)/m;
    }
    //减
    function sub(arg1,arg2){
        var r1,r2,m,n;
        try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
        try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
        m=Math.pow(10,Math.max(r1,r2));
        //动态控制精度长度
        n=(r1>=r2)?r1:r2;
        return ((arg1*m-arg2*m)/m).toFixed(n);
    }
    //乘
    function mul(arg1,arg2)   {
        var 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
    function div(arg1,arg2){
        var 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);
    }
    // exports
    return {
        add: add,
        sub: sub,
        mul: mul,
        div: div
    }
}();
export default bigDecimal;

不保留两位小数：

 getEntScalePre() {
                // debugger
                if ((this.viewForm.agencyQuickTotal == 0 || this.viewForm.agencyQuickTotal == null || this.viewForm.agencyQuickTotal == "")
                    || (this.viewForm.rdTotal == 0 || this.viewForm.rdTotal == null || this.viewForm.rdTotal == "")
                    || (this.viewForm.slTotal == 0 || this.viewForm.slTotal == null || this.viewForm.slTotal == "")
                    || (this.viewForm.sjTotal == 0 || this.viewForm.sjTotal == null || this.viewForm.sjTotal == "")) {
                    this.$error("四家中有可能没有给出估出价值，请转人工");
                    return;
                } else {
                    this.viewForm.systemTotal = bigDecimal.add(bigDecimal.mul(this.viewForm.agencyQuickTotal, 0.1024), bigDecimal.mul(this.viewForm.rdTotal, 0.1867));
                    this.viewForm.systemTotal = bigDecimal.add(this.viewForm.systemTotal, bigDecimal.mul(this.viewForm.slTotal, 0.3952));
                    this.viewForm.systemTotal = bigDecimal.add(this.viewForm.systemTotal, bigDecimal.mul(this.viewForm.sjTotal, 0.2531));
                    this.viewForm.systemTotal = (bigDecimal.add(this.viewForm.systemTotal, 17.89));
                    this.rgVisible = false;
                    this.$nextTick(() => {
                        this.rgVisible = true;
                    })
                }

在这里插入图片描述

保留两位小数：

 getEntScalePre() {
                // debugger
                if ((this.viewForm.agencyQuickTotal == 0 || this.viewForm.agencyQuickTotal == null || this.viewForm.agencyQuickTotal == "")
                    || (this.viewForm.rdTotal == 0 || this.viewForm.rdTotal == null || this.viewForm.rdTotal == "")
                    || (this.viewForm.slTotal == 0 || this.viewForm.slTotal == null || this.viewForm.slTotal == "")
                    || (this.viewForm.sjTotal == 0 || this.viewForm.sjTotal == null || this.viewForm.sjTotal == "")) {
                    this.$error("四家中有可能没有给出估出价值，请转人工");
                    return;
                } else {
                    this.viewForm.systemTotal = bigDecimal.add(bigDecimal.mul(this.viewForm.agencyQuickTotal, 0.1024), bigDecimal.mul(this.viewForm.rdTotal, 0.1867));
                    this.viewForm.systemTotal = bigDecimal.add(this.viewForm.systemTotal, bigDecimal.mul(this.viewForm.slTotal, 0.3952));
                    this.viewForm.systemTotal = bigDecimal.add(this.viewForm.systemTotal, bigDecimal.mul(this.viewForm.sjTotal, 0.2531));
                    this.viewForm.systemTotal = (bigDecimal.add(this.viewForm.systemTotal, 17.89)).toFixed(2);
                    this.rgVisible = false;
                    this.$nextTick(() => {
                        this.rgVisible = true;
                    })
                }

在这里插入图片描述