js导出Excel表格超出26位英文字符的解决方法ES6

/**
*json数据导入导出Excel表格示例代码
*
/
 
var array_utils = require('./utils-array')
var XLSX = require("xlsx");

module.exports = {
 writeExcel : function (headers,data,file,callback) {
  if(data.length ==0){
   var obj = {}
   for(var v of headers){
    obj[v] = ''
   }
   data.push(obj)
  }
  _writeExcel(headers,data,file,callback)
 },

 /**
  * 获取excel原始信息
  * @param path 文件路径
  */
 info : function(path){
  return _info(path)
 },
 /**
  * 格式化excel原始信息
  * @param path 文件路径
  */
 formate_info : function (path) {
  return info_formate_info(path).formate
 },
 info_formate_info : function (path) {
  return info_formate_info(path)
 }

}

var _info = function(path) {
 var k = XLSX.readFile(path, {type: 'base64'});
 var result = {}
 k.SheetNames.forEach(function(sheetName) {
  var worksheet = k.Sheets[sheetName];
  result[sheetName] = XLSX.utils.sheet_to_json(worksheet);
 });
 return result
}

var info_formate_info = function(path){
 var info = _info(path)
 var result = {}
 for(var value in info){
  result[value] = {}
 }
 for(var key_info in info ){
  var array = info[key_info]
  if(array_utils.isArray(array) || array.length>0){
   var keys_array = Object.keys(array[0])
   var obj = {}
   for(var value of keys_array){
    obj[value] = []
   }
   for( var key in obj ){
    var subject_clone = JSON.parse(JSON.stringify(array))
    subject_clone.filter( (v)=>{
     for(var k in v){
      if(k!=key){
       delete v[k]
      }
     }
     return v;
    })
    var subject_key_value = Array.from(array_utils.arrayQC(subject_clone),v => v[key] )
    var obA = []
    for(var v of subject_key_value){
     var obk = {
      id : null,
      v : v
     }
     for(var ke in keys_array){
      var thisIndex = keys_array.findIndex(x=>x==keys_array[ke])
      var currentIndex = keys_array.findIndex(x=>x==key)
      if( thisIndex < currentIndex){
       try {
        var thisObj = array.find(x=>x[ key ] == v )
        obk[keys_array[ke]] = thisObj[ keys_array[ke] ]
       }catch (e){
        console.error(e)
       }
      }
     }

     obA.push(obk)
    }
    obj[key] = obA
   }
   result[key_info]= obj
  }
 }
 return {
  info : info,
  formate : result
 }
}

var _writeExcel = function (headers,data,file,callback) {
 var _headers = headers
 var _data = data;
 var headers = _headers
 // 为 _headers 添加对应的单元格位置
  .map((v, i) => Object.assign({}, {
   v: v,
   position:num(i)+1
  }))
  // 转换成 worksheet 需要的结构
  .reduce((prev, next) => Object.assign({}, prev, {[next.position]: {v: next.v}}), {});
 var data = _data
  .map((v, i) => _headers.map((k, j) => Object.assign({}, {
   v: v[k],
   position:num(j) + (i+2)
  })))
  // 对刚才的结果进行降维处理（二维数组变成一维数组）
  .reduce((prev, next) => prev.concat(next))
  // 转换成 worksheet 需要的结构
  .reduce((prev, next) => Object.assign({}, prev, {[next.position]: {v: next.v}}), {});
// 合并 headers 和 data
 // console.log("测试data",data)
 var output = Object.assign({}, headers, data);
// 获取所有单元格的位置
 var outputPos = Object.keys(output);
// 计算出范围
 var ref = outputPos[0] + ':' + outputPos[outputPos.length - 1];
// 构建 workbook 对象
 var wb = {
  SheetNames: ['Sheet1'],
  Sheets: {
   'Sheet1': Object.assign({}, output, { '!ref': ref })
  }
 };

 // 导出 Excel
 XLSX.writeFileAsync( file , wb,function (err) {
  callback(err)
 });
}
//定位Excel位置
var num=function(i){
 var n=parseInt(i+65)
 if(n>90){
  n=String.fromCharCode(65)+String.fromCharCode(i+39)
  return n
 }else {
  n=String.fromCharCode(n)
  return n
 }

}