前端js浮点型加减乘除

import Vue from "vue";

/**
 * 浮点型加法
 */
Vue.prototype.$numAdd = function(num1, num2) {
   if( !validateParamsOfType(num1) || !validateParamsOfType(num2) ) {
      return 0
   }

   let r1, r2, m, n;
   try {
      r1 = num1.toString().split(".")[1].length
   } catch (e) {
      r1 = 0
   }
   try {
      r2 = num2.toString().split(".")[1].length
   } catch (e) {
      r2 = 0
   }
   m = Math.pow(10, Math.max(r1, r2))
   n = (r1 >= r2) ? r1 : r2;
   return ((num1 * m + num2 * m) / m).toFixed(n);
}

/**
 * 浮点型减法
 */
Vue.prototype.$numSub = function(num1, num2) {
   if( !validateParamsOfType(num1) || !validateParamsOfType(num2) ) {
      return 0
   }

   let re1, re2, m, n;
   try {
      re1 = num1.toString().split(".")[1].length;
   } catch (e) {
      re1 = 0;
   }
   try {
      re2 = num2.toString().split(".")[1].length;
   } catch (e) {
      re2 = 0;
   }
   m = Math.pow(10, Math.max(re1, re2));
   n = (re1 >= re2) ? re1 : re2;
   return ((num1 * m - num2 * m) / m).toFixed(n);
}

/**
 * 浮点型乘法
 */
Vue.prototype.$numMul = function(num1, num2) {
   if( !validateParamsOfType(num1) || !validateParamsOfType(num2) ) {
      return 0
   }

   let m = 0;
   let s1 = num1.toString();
   let s2 = num2.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);
}

/**
 * 浮点型除法
 * @param num1 除数
 * @param num2 被除数
 * @param digit 保留的小数点后的位数
 */
Vue.prototype.$numDiv = function (num1, num2, digit=2){
   if( !validateParamsOfType(num1) || !validateParamsOfType(num2) ) {
      return 0
   }

   let t1=0,t2=0,r1,r2;
   try{t1=num1.toString().split(".")[1].length}catch(e){}
   try{t2=num2.toString().split(".")[1].length}catch(e){}
   r1=Number(num1.toString().replace(".",""))
   r2=Number(num2.toString().replace(".",""))
   //获取小数点后的计算值
   let result = ((r1/r2)*Math.pow(10,t2-t1)).toString()
   let result2 = result.split(".")[1] ? result.split(".")[1] : '';
   result2=result2.substring(0,digit>result2.length?result2.length:digit);
   return Number(result.split(".")[0]+"."+result2);
}

/**
 * 验证参数是否为string、number类型
 */
function validateParamsOfType(params) {
   return ['number', 'string'].includes(typeof params);

}