var tabledata = [
    {id:1, distance:"42", time:"13.90", speed:""},
    {id:2, distance:"12", time:"5.70", speed:""},
];
//custom mutator
var speedMutator = function(value, data, type, params, component){
    return Math.round(data.distance / data.time);
}
var table = new Tabulator("#example-table", {
    data:tabledata,
    columns:[ //Define Table Columns
        {title:"Id", field:"id", visible:false},
        {title:"Distance", field:"distance", editor:true},
        {title:"Time", field:"time", editor:true},
        {title:"Speed", field:"speed", mutator:speedMutator, mutatorEdit:speedMutator},
    ],
});