js计算精度丢失解决方法

//加法

function add(num1,num2) {
	let len1R,len2R,totalPow 
	function getLen(num){
		let lenL,lenR 
		try {
			lenL = num.toString().split(".")[0].length
			lenR = num.toString().split(".")[1].length
		}catch(err){
			lenL = 0
			lenR = 0
		}
		//获取长度最长的值
		return [ lenL,lenR]
	}
	let arrLen1=getLen(num1)
	let arrLen2=getLen(num2)
	len1R=arrLen1[1]
	len2R=arrLen2[1]
	totalPow = Math.pow(10,Math.max(len1R,len2R))
	num1=Number(num1.toString().replace(".",""))
	num2=Number(num2.toString().replace(".",""))
	let gapPow = Math.pow(10,Math.abs(len1R-len2R))
	if(len1R<len2R){
		num1=num1*gapPow 
	}else{
		num2=num2*gapPow 
	}
	return (num1+num2)/totalPow
}