NodeJS生成Excel

　　原本只是想寫個NodeJS爬蟲，中間涉及到一點Excel。找了找Excel模塊，xlsx模塊在npm官網上搜索排名很靠前，就選了它，star數還比較可觀。仔細瞭解了xlsx模塊才發現這玩意生成Excel文件實在太麻煩，搜索網上的博客，那些人都是互相抄襲，代碼也不夠優雅。得了，仍是我本身造輪子吧。
　　註釋很詳細，直接上代碼：

const XLSX = require('xlsx');
    
    class WorkBook {
        /**
         * @param {Object} data Excel表格源數據，格式以下：
         * {
         *      Sheet1: [
         *          ['姓名', '學號', '籍貫'],
         *          ['lxz', '10131911', 'hunan']
         *      ]
         * }
         */
        constructor(srcData) {
            this.srcData = srcData;
            this.workbook = {};
            this.workbook.SheetNames = [];
            this.workbook.Sheets = {};
    
            for(let item in srcData) {
                this.workbook.SheetNames.push(item);
                this.addSheet(item, srcData[item]);
            }
        }
    
        /**
         * 往Excel文件添加一個表格
         * @param {string} sheetName 表格名
         * @param {object} sheet 表格數據
         * @returns void
         */
        addSheet(sheetName, sheet) {
            this.workbook['Sheets'][sheetName] = {};
            let row = sheet.length;
            let col = sheet[0].length;
            let to = '';
    
            for(let i=0; i<row; i++) {
                for(let j=0; j<col; j++) {
                    let key = this.ten2twentysix(j+1) + (i+1);
                    this.workbook['Sheets'][sheetName][key] = {'v': sheet[i][j]};
                    to = key;
                }
            }
            this.workbook['Sheets'][sheetName]['!ref'] = 'A1:' + to;
        }
    
    
        /**
         * 10進制轉26進制
         * @param {number} num 正整數
         * @returns string
         */
        ten2twentysix(num) {
            let str = '';
            while(num) {
                let rest = num % 26;
                num = (num-rest) / 26;
                str += String.fromCharCode(rest + 64);
            }
    
            let twentysixNumber = '';
            let len = str.length;
            for(let i=len-1; i>=0; i--) {
                twentysixNumber += str[i];
            }
    
            return twentysixNumber;
        }
    
        /**
         * 將數據寫入Excel
         * @param {string} filename 文件路徑
         */
        writeFile(filename) {
            XLSX.writeFile(this.workbook, filename);
        }
    }
    
    module.exports = WorkBook;