JAVASCRIPT

jquery get checked checkbox values array

let weekdays = $('input[name="weekday"]:checked').map(function () {
  return $(this).val()
}).get()

jquery get selected checkbox value array

$("#merge_button").click(function(event){
    event.preventDefault();
    var searchIDs = $("#find-table input:checkbox:checked").map(function(){
      return $(this).val();
    }).get(); // <----
    console.log(searchIDs);
});