I am a beginner in coding just started with node.js ,I want to send an excel file from client side to server side using ajax post method. But while trying this code I am getting error 'BadRequestError: Only json objects or array allowed'. Can someone please tell me what I am doing wrong here.

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


$scope.fileUpload = function() {
    const myFile = document.getElementById("myFile").files;
    var formData = new FormData();

    for (var i =0; i<myFile.length; i++) {
        formData.append("myFile", myFile[i]);
    }
    dataFactory.post("/excel.json", formData).then(function(res) {
        console.log(res);
    }, function() {

    });
  };

  Error :POST http://localhost:5000//excel.json 500 (Internal Server Error)