给定下表描述：

<script>
    var customMutator = function(value, data, type, params, component){
        return data.category_name + " " + data.short_description;
    } ;

    var tabledata = [
    {id:1, category_name:"IT", short_description:"This is an IT message", long_description:"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.", valid_from:"2019-12-05T10:48:00", valid_to:"2018-12-04T22:00:00"},
    {id:2, category_name:"Bookeeping", short_description:"This is an bookeeping message", long_description:"Lorem ipsum dolor azaz sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.", valid_from:"2019-12-04T10:48:00", valid_to:"2019-12-04T22:00:00"},
    ];

    var printIcon = function(cell, formatterParams, onRendered){
        return '<span  style="color:blue;"><i class="far fa-edit"></i></span>';
    };

    var table = new Tabulator("#mb-table", {
        placeholder:"Keine Nachricht vorhanden...",
        height: window.innerHeight - 53,
        layout:"fitColumns",
        langs:{
            "de-de":{
                "headerFilters":{
                    "default":"Filtern..."
                }
            }
        },
        columns:[
            {title:"Kategorie", field:"category_name", headerFilter:true, width:120},
            {title:"Kat", field:"new_kat", mutator:customMutator, headerFilter:true, width:120},
            {title:"Nachricht", field:"short_description", headerFilter:true, formatter:function(cell, formatterParams){
                var val1 = cell.getValue();
                var val2 = cell.getRow().getData().long_description;
                cell.getElement().style.whiteSpace = "pre-wrap";

                return "<span style='font-weight:bold;'>" + val1 + "</span><br><span style='word-break: normal;'>" + val2 + "</<span>";
                }
            },
            {title:"Gültig von", field:"valid_from", headerFilter:true, width:110, sorter:"datetime", sorterParams:{format:"YYYY-MM-DDThh:mm:ss"},
                formatter:"datetime", formatterParams:{
                    inputFormat:"YYYY-MM-DDThh:mm:ss",
                    outputFormat:"DD.MM.YYYY hh:mm"
                },
            },
            {title:"Gültig bis", field:"valid_to", headerFilter:true, width:110, sorter:"datetime", sorterParams:{format:"YYYY-MM-DDThh:mm:ss"},
                formatter:"datetime", formatterParams:{
                    inputFormat:"YYYY-MM-DDThh:mm:ss",
                    outputFormat:"DD.MM.YYYY hh:mm"
                },
            },
            {formatter:printIcon, align:"center", width:10, headerSort:false,
                cellClick:function(e, cell){alert("Printing row data for: " + cell.getRow().getData().id)}},
            {formatter:"buttonCross", width:10, align:"center", headerSort:false,
                cellClick:function(e, cell){alert("Printing row data for: " + cell.getRow().getData().category_name)}},
        ]
    });

    table.setLocale("de-de");
    table.setData(tabledata);
</script>

我没有看到 Kat 列中显示任何内容。 我做错了什么？

编辑： 实际上，mutator 函数甚至没有被调用。 如果我将 console.log(data);（当然是在返回之前）放入函数中，我在控制台中看不到任何内容