js小数加减时精度不准确

Posted 2021-03-26 simple-love

// 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
}

// 返回值：arg1减去arg2的精确结果
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));
    // 动态控制精度长度
    n = (r1 >= r2) ? r1 : r2;
    return ((arg1 * m - arg2 * m) / m).toFixed(n);
}