Syntax help to create values list for table column

[waubain]

I am using Tablulator 4.1, which is a pure javascript library for tables. One column of my table provides a drop down list of values. I had this working by calling the function directly from editorParams:, but I got a warning that this method is being depreciated and to use the following method.

{title:"Room", field:"room", editor:"select", editorParams:{
    values:function(cell){

        //lookup values from data source

        return values;
}}},

I am having trouble adapting my method to the new method. Initially when I click on the cell, nothing happens, but if I click another cell, the list of values appears as it should and then every subsequent cell I click. . I think I must be close, but do not understand why it is not populating the list on first click.

            {title:"Room", field:"room", editor:"select", editorParams:{
                values:function(cell){
                    return getroomlist();}
            }},    



        function getroomlist() {
            var file = "../textfiles/room_array.txt";  
            var rawFile = new XMLHttpRequest();
                rawFile.open("GET", file, true);
                rawFile.onreadystatechange = function ()
                {
                    if(rawFile.readyState === 4)
                    {
                        if(rawFile.status === 200 || rawFile.status == 0)
                        {       
                            var data = JSON.parse(rawFile.responseText);
                        }
                                //roomlist = {};
                                window.roomlist = data.map(function(e)
				{       
                                return e.room;
                                });
                    }
                }
                rawFile.send(null);
                return window.roomlist;   
                }

 

[waubain]

If I change asynchronous from true to false, then it works. But I get a message in the console stating "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience.

rawFile.open("GET", file, false);