(JS) three digits are separated by commas, and two decimal places are reserved (or rounded)

//1,  Encapsulation method 
handleNum(num){
    
     //(1) Keep two decimal places 
	//var dot = String(num).indexOf(".");
	//if(dot != -1){
    
	//var dotCnt = String(num).substring(dot+1,num.length);
		//if(dotCnt.length > 2) num = num.toFixed(2);
	//}
	//(2) Round to the nearest whole number 
	 num = Math.round(num)
	 // Three digit separation 
	return String(num).replace(/\d+/, function(n) {
    
		return  n.replace(/(\d)(?=(?:\d{3})+$)/g, '$1,');
	});
},

//2, call , Pass in the number type 
onLoad() {
    
	console.log(this.handleNum(1234.0285678)); 
},