JavaScript(js)でcsvファイルを読み込み自動計算する(合計sum)

"use strict";
class CsvCalc
{
	constructor (filename,elementId) 
	{
		this.filename = filename;
		this.elementId = elementId;
		this.datas = null;
		this.sum = [];
	}
	async getData()
	{
		try {
			const response = await fetch(this.filename);
			if (!response.ok) throw new Error(`HTTP Error: ${response.status}`);
			this.datas = await response.text();
		} catch (err) {
			console.error("データ取得エラー:", err);
			this.datas = "";
		}
		return this;
	}
	csvSplit()
	{	
		let separate1 = /\r?\n/;
		let separate2 = ",";
		let datas = (this.datas?.split(separate1))?.map(function(row){
			return (row?.split(separate2))?.map(function(col){
				return col;
			});
		});
		this.datas = datas.filter(row => row.length > 0);
		return this;
	}
	getSum()
	{
		let sum =[];
		for (const data of this.datas) {
            (data).map(function(val,index,array){
                sum[index] = (isNaN(parseInt(sum[index]))?0:parseInt(sum[index])) + parseInt(array[index]);
            });
		}
		this.sum = sum;
		return this;
	}

	printSum()
	{
		document.getElementById(this.elementId).textContent = this.sum.join(',');
	}
}

(async ()=>{
	await (new CsvCalc("math.csv?", "sum"))
		.getData()
		.then(obj => obj.csvSplit().getSum().printSum());
})();