Google Sheets App Script for Multiple-column range-wide auto-sort

code.gs

function onEdit(event) {
  var sheet = SpreadsheetApp.getActiveSheet();
  var editedCell = sheet.getActiveCell();
  
  var rangeValue = "A2:D";
  var columns = [3, 2, 1];
  var ascendings = [true, false, true];
 
  if (editedCell.getColumn() in columns) {
    var range = sheet.getRange(rangeValue);
    var args = columns.map(function(elem, index) {
      return {column: elem, ascending: ascendings[index]};
    });
    range.sort(args);
  }
}