test.js

function insertTableWithText() {
  // start the undo action (open group)
  TXTextControl.beginUndoAction("Table insertion");

  // add a table
  TXTextControl.tables.add(5, 5, 10, function(e) {
    if (e === true) { // if added
      TXTextControl.tables.getItem(async function(table) {
        console.log("setting cell text...");

        // async setting of cell text 	
        await setCellText(table);

        console.log("setting cell text done.");

        // stop the undo action (close group)
        TXTextControl.endUndoAction();
      }, null, 10);
    }
  })
}

function setCellText(table) {
  return new Promise(resolve => {
    table.cells.getCount(function(count) {

      // loop through all table cells
      for (let i = 0; i < count; i++) {
        table.cells.elementAt(i, function(cell) {

          console.log("setting text for cell " + i);
          cell.setText("Cell " + i);

          // resolve on last cell
          if (i == count - 1) {
            resolve();
          }

        });
      }
    });
  });
}