出现错误：TypeError：无法读取 null 的属性（读取“0”）

Question

I want to upload an excel file for that I used ng-click and define the fileUpload($event) function in the app controller scope and with the help of xlsx I want to read the file in JSON but while running the code getting this error-

 <div>
     <input id="file-upload" type="file"/>
     <input type="button" value="Upload" ng-click ="fileUpload($event)">
 </div>

   $scope.fileUpload = function(mE) {
        const file = mE.target.files[0];
        const fileReader = new FileReader();
        fileReader.readAsBinaryString(file);
        fileReader.onload = (e) => {
            var workBook = XLSX.read(fileReader.result, {type: 'binary'});
            var sheetNames = workBook.SheetNames;
            var ExcelData = XLSX.utils.sheet_to_json(workBook.Sheets[sheetNames[0]]);
                console.log(ExcelData);
         };
     };

 TypeError: Cannot read properties of null (reading '0')
 at $scope.fileUpload 
 at site.js?ver=1:1:47308
 at t (site.js?ver=1:1:5384)
 at a.$eval (site.js?ver=1:1:4894)
 at a.$apply (site.js?ver=1:1:4119)
 at HTMLInputElement.<anonymous> (site.js?ver=1:1:5035)
 at HTMLInputElement.dispatch (site.js?ver=1:1:200)
 at p.handle (site.js?ver=1:1:40)

Answer 1

Try this in your fileUpload function

const file  = document.getElementById('file-upload').files[0];
...