fix: 商品单位是小数时,合计值问题

src/pages/lxMall/commodityDetail/index.tsx

@@ -861,11 +861,37 @@ const CommodityDetail = (props) => {
    */
   const getAmount = (state = true) => {
     const unitPrice = getUnitPrice()
-    const amount = unitPrice * (Number(buyCount) || 0)
+    const amount = accMul(unitPrice, buyCount)
     return state ? priceFormat(amount) : amount
   }
 
   /**
+   ** 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
+  **/
+  const accMul = (arg1: number, arg2: number) => {
+    if(!arg1 || !arg2){
+      return 0
+    }
+    let m = 0
+    const s1 = arg1.toString()
+    const s2 = arg2.toString()
+    try {
+      m += s1.split(".")[1].length;
+    } catch (e) {
+      console.log(e)
+    }
+    try {
+      m += s2.split(".")[1].length;
+    } catch (e) {
+      console.log(e)
+    }
+    return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
+  }
+
+  /**
    * 获取金额区间中数量最大的区间
    */
   const getMaxCountRange = () => {