vue封装公共方法处理js计算科学记数法精度问题

第1种方法 来源:https://blog.csdn.net/zxz8023915/article/details/107780423

 第一步 新建一个 js 放入公共文件夹

//除法函数,用来得到精确的除法结果
//说明:javascript的除法结果会有误差,在两个浮点数相除的时候会比较明显。这个函数返回较为精确的除法结果。
//调用:accDiv(arg1,arg2)
//返回值:arg1除以arg2的精确结果
function accDiv(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(".", ""));
  if(r2==0){
    return Infinity;
  }else{
    return (r1 / r2) * Math.pow(10, t2 - t1);
	}
}
//乘法函数,用来得到精确的乘法结果
//说明:javascript的乘法结果会有误差,在两个浮点数相乘的时候会比较明显。这个函数返回较为精确的乘法结果。
//调用:accMul(arg1,arg2)
//返回值:arg1乘以arg2的精确结果
function accMul(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);
}
//加法函数,用来得到精确的加法结果
//说明:javascript的加法结果会有误差,在两个浮点数相加的时候会比较明显。这个函数返回较为精确的加法结果。
//调用:accAdd(arg1,arg2)
//返回值:arg1加上arg2的精确结果
function accAdd(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;
}
//减法函数
function accSub(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));
	//last modify by deeka
	//动态控制精度长度
	n = (r1 >= r2) ? r1 : r2;
	return ((arg2 * m - arg1 * m) / m).toFixed(n);
}


//给Number类型增加一个add方法,调用起来更加方便。
Number.prototype.add = function (arg) {
	return accAdd(arg, this);
};
//给Number类增加一个sub方法,调用起来更加方便
Number.prototype.sub = function (arg) {
	return accSub(arg, this);
};
//给Number类型增加一个mul方法
Number.prototype.mul = function (arg) {
	return accMul(arg, this);
};
//给Number类型扩展一个div方法
Number.prototype.div = function (arg) {
	return accDiv(this, arg);
};

export {
  accDiv,
  accMul,
  accAdd,
  accSub,
}

  第二步 引入 

 

打印结果:

 

第二种方法 来源:https://blog.csdn.net/zuorishu/article/details/83108988?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2~all~first_rank_v2~rank_v25-5-83108988.nonecase&utm_term=vue%E8%A7%A3%E5%86%B3%E7%B2%BE%E5%BA%A6%E9%97%AE%E9%A2%98

  1.新建公共方法的js文件,我为这个单独建了一个文件:

 calculation.js 代码:

var countDecimals = function(num) {
    var len = 0;
    try {
        num = Number(num);
        var str = num.toString().toUpperCase();
        if (str.split('E').length === 2) { // scientific notation
            var isDecimal = false;
            if (str.split('.').length === 2) {
                str = str.split('.')[1];
                if (parseInt(str.split('E')[0]) !== 0) {
                    isDecimal = true;
                }
            }
            let x = str.split('E');
            if (isDecimal) {
                len = x[0].length;
            }
            len -= parseInt(x[1]);
        } else if (str.split('.').length === 2) { // decimal
            if (parseInt(str.split('.')[1]) !== 0) {
                len = str.split('.')[1].length;
            }
        }
    } catch (e) {
        throw e;
    } finally {
        if (isNaN(len) || len < 0) {
            len = 0;
        }
        return len;
    }
};
 
var convertToInt = function(num) {
    num = Number(num);
    var newNum = num;
    var times = countDecimals(num);
    var temp_num = num.toString().toUpperCase();
    if (temp_num.split('E').length === 2) {
        newNum = Math.round(num * Math.pow(10, times));
    } else {
        newNum = Number(temp_num.replace(".", ""));
    }
    return newNum;
};
 
var getCorrectResult = function(type, num1, num2, result) {
    var temp_result = 0;
    switch (type) {
        case "add":
            temp_result = num1 + num2;
            break;
        case "sub":
            temp_result = num1 - num2;
            break;
        case "div":
            temp_result = num1 / num2;
            break;
        case "mul":
            temp_result = num1 * num2;
            break;
    }
    if (Math.abs(result - temp_result) > 1) {
        return temp_result;
    }
    return result;
};
export default {
    //加法
    accAdd(num1, num2) {
        num1 = Number(num1);
        num2 = Number(num2);
        var dec1, dec2, times;
        try { dec1 = countDecimals(num1) + 1; } catch (e) { dec1 = 0; }
        try { dec2 = countDecimals(num2) + 1; } catch (e) { dec2 = 0; }
        times = Math.pow(10, Math.max(dec1, dec2));
        // var result = (num1 * times + num2 * times) / times;
        var result = (this.accMul(num1, times) + this.accMul(num2, times)) / times;
        return getCorrectResult("add", num1, num2, result);
        // return result;
    },
    //减法
    accSub(num1, num2) {
        num1 = Number(num1);
        num2 = Number(num2);
        var dec1, dec2, times;
        try { dec1 = countDecimals(num1) + 1; } catch (e) { dec1 = 0; }
        try { dec2 = countDecimals(num2) + 1; } catch (e) { dec2 = 0; }
        times = Math.pow(10, Math.max(dec1, dec2));
        // var result = Number(((num1 * times - num2 * times) / times);
        var result = Number((this.accMul(num1, times) - this.accMul(num2, times)) / times);
        return getCorrectResult("sub", num1, num2, result);
        // return result;
    },
    //除法
    accDiv(num1, num2) {
        num1 = Number(num1);
        num2 = Number(num2);
        var t1 = 0,
            t2 = 0,
            dec1, dec2;
        try { t1 = countDecimals(num1); } catch (e) {}
        try { t2 = countDecimals(num2); } catch (e) {}
        dec1 = convertToInt(num1);
        dec2 = convertToInt(num2);
        var result = this.accMul((dec1 / dec2), Math.pow(10, t2 - t1));
        return getCorrectResult("div", num1, num2, result);
        // return result;
    },
    //乘法
    accMul(num1, num2) {
        num1 = Number(num1);
        num2 = Number(num2);
        var times = 0,
            s1 = num1.toString(),
            s2 = num2.toString();
        try { times += countDecimals(s1); } catch (e) {}
        try { times += countDecimals(s2); } catch (e) {}
        var result = convertToInt(s1) * convertToInt(s2) / Math.pow(10, times);
        return getCorrectResult("mul", num1, num2, result);
        // return result;
    }
}

  2.在main.js 引入 全局使用

import cal from './utils/calculation'
Vue.prototype.cal = cal

  2.1 全局引入之后再  组件中使用

//加法
this.cal.accAdd(2,1);
//减法
this.cal.accSub(2,1);
//除法
this.cal.accDiv(2,1);
//乘法
this.cal.accMul(2,1);
 
console.log(this.cal.accAdd(2,1))   // 3
console.log(this.cal.accSub(2,1))   // 1
console.log(this.cal.accDiv(2,1))   // 2
console.log(this.cal.accMul(2,1))   // 2

  

3. 在每个单独的页面中使用

原文地址:https://www.cnblogs.com/li-sir/p/13719415.html