Import excel file using angular and convert that excel sheet data in array using REST API in .net core

Question

The frontend is in Angular. The backend is in .net Core.

1. trying to develop an import excel sheet functionality so in the frontend, I am using angular where I want to import the file and I need to convert that excel data into array format or in JSON
2. for convert excel into an array I want one rest API in .net core ( i don't want to use XSLX PAckage from angular)

this method I developed, here I am passing FILE as bsae64 in request body to these API

   public async Task<dynamic> converexceltotAray()
    {
        using (StreamReader steamread = new StreamReader(Request.Body, System.Text.Encoding.UTF8))
        {
            string s = await steamread.ReadToEndAsync();
            byte[] newBytes = Convert.FromBase64String(s);
            using (MemoryStream stream = new MemoryStream(newBytes)) {
                byte[] bytes = stream.ToArray();
                var reader = ExcelReaderFactory.CreateReader(stream);
            var result = reader.AsDataSet(new ExcelDataSetConfiguration()
            {
                ConfigureDataTable = (_) => new ExcelDataTableConfiguration()
                {
                    //ReadHeaderRow = (rowReader) => {
                    // for(int i=0;i<3;i++)
                    // {
                    // rowReader.Read();
                    // }
                    //},
                    UseHeaderRow = true,
                }
            });
            DataTable table = result.Tables[1];
            //dataGridView1.DataSource = table;
            string json = JsonConvert.SerializeObject(table, Formatting.Indented);
            //rtxtOutPut.Text = json;
            //stream.Close();
            return json;
        }
        }
    }