HTMLTableRowElement: insertCell()

insertCell()
insertCell(index)

<table id="my-table">
  <tr>
    <td> 1</td>
  </tr>
  <tr>
    <td> 2</td>
  </tr>
  <tr>
    <td> 3</td>
  </tr>
</table>

function addRow(tableID) {
  // 
  let tableRef = document.getElementById(tableID);

  // 
  let newRow = tableRef.insertRow(-1);

  //  0 
  let newCell = newRow.insertCell(0);

  // 
  let newText = document.createTextNode("");
  newCell.appendChild(newText);
}

// addRow()  ID 
addRow("my-table");