You can do something like (untested):
var
JSObj: TJSObject;
JSArr: TJSArray;
begin
JSObj := TJSObject.new;
JSArr := TJSArray,new;
JSObj['Type'] := 'example...';
JSObj['Table1data'] := JSArr;
tmytable.First;
while not tmytable.Eof do
begin
Rows.push(tmytable.CurrentData);
tmytable.Next;
end;
vResponse := await(vClient.RawInvokeAsync(vEndPoint, [JSObj]));