Removing row from table results in TypeError

Question

I have a ReactJS HTML table component and I update its content (cell values) with the setState method. Here is the basic code:

 var Cell = React.createClass({
  render: function () {
    return (<td>{this.props.cellValue}</td>);
      }
    });

 var Row = React.createClass({
  render: function () {
     return (<tr>{this.props.row}</tr>);
   }
  });

var Table = React.createClass({
  getInitialState: function() {
    return {
      data: this.props.data
    };
  },
  render: function () {
    return (
      <table>
      {
        this.state.data.map(function(row) {
          var r = row.map(function(cell) {
            return <Cell cellValue={cell}/>;
          });

          return (<Row row={r}/>);
        })
      }
      </table>
     );
  }});

You would use it like this:

var initialData = [[1,2,3],[4,5,6],[7,8,9]];
var table = React.renderComponent(
  <Table data={initialData} />,
  document.getElementById('table')
);

This is working most of the time. I can change the data by doing this (somewhere in a function or whatever):

var newData = [[1,2,3],[4,5,6],[7,8,9],[10,11,12]];
table.setState({data : newData});

As you can see, it adds one row to the end of the table. However, if I try to set the initial data after this update or in any way shorten the number of rows by setting data to a smaller array (e. g. [[1, 2, 3], [4, 5, 6]] which should remove the last row):

table.setState({data : initialData});

I get this error:

TypeError: updatedChildren[j] is undefined updatedChildren[j].parentNode.removeChild(updatedChildren[j]);

Where does it come from?

Answer 1

Some browsers (tested with Firefox and Chrome) add automatically <tbody>...</tbody> tags to an HTML table that does not have them. Adding them in my Table component fix the issue:

render: function () {
    return (
      <table><tbody>
      {
        ... same code as before ...
      }
      </tbody></table>
     );

If you look at the html code generated by React, you can notice it adds some data attributes (data-reactid) to all the HTML tags rendered by a React component (to more info about data attribute in general: go here). Since the <tbody>...</tbody> tags was not from a React component, they did not have any data-reactid and these attributes help React to track DOM nodes.

Anyway, thank you to these people who talked about this issue. Here the link https://groups.google.com/forum/#!topic/reactjs/NLs-PdrdDMA.

More about data-reactid: https://groups.google.com/forum/#!topic/reactjs/ewTN-WOP1w8.