How to call Datatable csv button from custom button

dataTables export buttons is by default enriched with signature classes like .buttons-excel, .buttons-pdf, .buttons-csv and so on. Take advantage of that :

$('#ExportReporttoExcel').on('click', function() {
  $('.buttons-excel').click()
});

Say you have your own button

<a href="javascript:;" style="some button style" class="button_export_excel">Export Excel</a>

And you have your table that you are using the below code for;

$(document).ready(function () {
    var table = $('#example').DataTable({
        "paging": false,
        "info": false,
        searching: false,
        dom: 'Bfrtip',
        buttons: [
            {
                extend: 'excelHtml5'
            }
        ]
    });
});

Then all you need to do is to use this code below:

$('#example').DataTable({
        "paging": false,
        "info": false,
        buttons: [
            {
                extend: 'excel'
            },
            {
                extend: 'csv'
            },
        ]
    });
$('.button_export_excel').click(() => {
    $('#example').DataTable().buttons(0,0).trigger()
})

The 0,0 points to excel and if you want to point to csv you do 0,1.

At last i found the solution.

In Datatable configuration , i added click event for the button to be triggered.

buttons: [
        { 
            extend: 'csv',
        }
    ]

$("#ExportReporttoExcel").on("click", function() {
    table.button( '.buttons-csv' ).trigger();
});

This works fine for me thanks for the comments and answers