js 浮点数加减乘除 小数不报错

错误： 下边的算法数字足够大时还是会出现问题

function add(a, b) {

 const m=1000000000；

 return  (a*m + b*m)  /m

}

正确：

function add(a, b) {
var c, d, e;
try {
c = a.toString().split(".")[1].length;
} catch (f) {
c = 0;
}
try {
d = b.toString().split(".")[1].length;
} catch (f) {
d = 0;
}
return e = Math.pow(10, Math.max(c, d)), (mul(a, e) + mul(b, e)) / e;
}

function sub(a, b) {
var c, d, e;
try {
c = a.toString().split(".")[1].length;
} catch (f) {
c = 0;
}
try {
d = b.toString().split(".")[1].length;
} catch (f) {
d = 0;
}
return e = Math.pow(10, Math.max(c, d)), (mul(a, e) - mul(b, e)) / e;
}

function mul(a, b) {
var c = 0,
d = a.toString(),
e = b.toString();
try {
c += d.split(".")[1].length;
} catch (f) {}
try {
c += e.split(".")[1].length;
} catch (f) {}
return Number(d.replace(".", "")) * Number(e.replace(".", "")) / Math.pow(10, c);
}

function div(a, b) {
var c, d, e = 0,
f = 0;
try {
e = a.toString().split(".")[1].length;
} catch (g) {}
try {
f = b.toString().split(".")[1].length;
} catch (g) {}
return c = Number(a.toString().replace(".", "")), d = Number(b.toString().replace(".", "")), mul(c / d, Math.pow(10, f - e));
}

原文链接：https://blog.csdn.net/qinshenxue/article/details/43671763