trigger javascript from onclick in Dash

Question

I have a Python Dash app running, with a couple of callbacks and a nice looking graph. What I need next, is to have a button for copying some results to the cliboard in excel format (pretty specific, yup). I guess I need to implement a javascript function triggered by a button onclick, but I have no idea how to get the Python app to call the javascript. Can somebody help me out with this one? :)

something like this:

function copy_to_cliboard() {
  var copyText = document.getElementById("text_input");

  copyText.select();
  copyText.setSelectionRange(0, 99999);

  document.execCommand("copy");

  alert("Copied the text: " + copyText.value);
}

thanks a lot!

Answer 1

In case some one is experiencing the same challenge, below is my solution.

app.clientside_callback(
    """
    function placeholder(n_clicks, data) {
        window.data_to_copy = data.data;
        var copyText = document.getElementById("text_input");
        copyText.select();
        copyText.setSelectionRange(0, 99999);
        document.execCommand("copy");
    }

    // Overwrite what is being copied to the clipboard.
    document.addEventListener('copy', function(e){
      // e.clipboardData is initially empty, but we can set it to the
      // data that we want copied onto the clipboard.
      e.clipboardData.setData('text/plain', window.data_to_copy);

      // This is necessary to prevent the current document selection from
      // being written to the clipboard.
      e.preventDefault();
    });
    """,
    [Output("copy_output", "children")],
    [Input("copy_button", "n_clicks")],
    [State("excel_output", "data")]
)