js实现加减乘除计算js丢失精度

- 日理万妓 2022-01-12 13:35 291阅读 0赞

/\*\*

*  公用方法  
    */  
    /*\*\*\*\*\*\*\*应用于几乎所有页面\*\*\*\*\*\*\*\*\*\*\*\*\*\* \*/  
    /\*\*
 *  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。  
    返回值：arg1加上arg2的精确结果  
    
 *  @param \{\*加数\} arg1
 *  @param \{\*加数\} arg2
 *  @param \{ *是否需要格式化\} needFormat*  
    /  
    function accAdd(arg1, arg2, needFormat) \{  
    arg1 = parseFloat(arg1 + "");  
    arg2 = parseFloat(arg2 + "");  
    if (isNaN(arg1)) \{  
    arg1 = 0;  
    \}  
    if (isNaN(arg2)) \{  
    arg2 = 0;  
    \}  
    var result = (arg1 \* 100 + arg2 \* 100) / 100;  
    needFormat && (result = keepDecimalFull(result, $ANumPosition));  
    return parseFloat(result) === 0 ? '' : result;  
    \}

*  乘法
 *  @param \{\*\} arg1
 *  @param \{\*\} arg2
 *  @param \{ *是否需要格式化\} needFormat*  
    /  
    function accMulti(arg1, arg2, needFormat) \{  
    arg1 = parseFloat(arg1 + "");  
    arg2 = parseFloat(arg2 + "");  
    if (isNaN(arg1)) \{  
    arg1 = 0;  
    \}  
    if (isNaN(arg2)) \{  
    arg2 = 0;  
    \}  
    var result = arg1 \* arg2;  
    needFormat && (result = keepDecimalFull(result, $ANumPosition));  
    return parseFloat(result) === 0 ? '' : result;  
    \}  
    /\*\*
 *  除法
 *  @param \{\*被除数\} Dividend
 *  @param \{\*除数\} Divisor
 *  @param \{\*是否需要格式化\} needFormat
 *  @param \{\*是否生成百分比\} isPercent
 *  @param \{ *额外的小数位数保留\} extraFormat*  
    /  
    function accDiv(Dividend, Divisor, needFormat, isPercent, extraFormat) \{  
    Dividend = parseFloat(Dividend + "");  
    Divisor = parseFloat(Divisor + "");  
    var result;
    
    if (isNaN(Dividend)) \{  
    Dividend = 0;  
    \}  
    if (isNaN(Divisor)) \{  
    Divisor = 0;  
    \}
    
    if (Divisor === 0) \{  
    result = 0;  
    \} else \{  
    if (isPercent) \{  
    result = Dividend \* 100 / Divisor;  
    \} else \{  
    result = Dividend / Divisor;  
    \}  
    \}  
    needFormat && (result = keepDecimalFull(result, extraFormat ? extraFormat : $ANumPosition));  
    return parseFloat(result) === 0 ? '' : result;  
    \}  
    /\*\*
 *  toFixed 四舍五入不精确 比如127.425
 *  @param \{\*数字\} num
 *  @param \{ *保留位数\} pos*  
    /  
    function keepDecimalFull(num, pos) \{  
    var result = parseFloat(num);  
    var decimal;  
    var pos = pos || 2;  
    var pos\_multiple = 100;
    
    // 放大倍数  
    if(pos)\{  
    pos\_multiple = 10;
    
        for(var i = 1;i < pos;i++){
             pos_multiple *= 10;
         }
    
    \}
    
    if (isNaN(result)) \{  
    result = 0;  
    \}  
    result = Math.round(num \* pos\_multiple) / pos\_multiple;
    
    decimal = result.toString();
    
    // 补充小数点  
    var pos\_decimal = decimal.indexOf('.');  
    if (pos\_decimal < 0) \{  
    pos\_decimal = decimal.length;  
    decimal += '.';  
    \}
    
    while (decimal.length <= pos\_decimal + pos) \{  
    decimal += '0';  
    \}  
    return decimal;  
    \}

转载于:https://www.cnblogs.com/zhtian/p/10537781.html