ReactJS test of table rendering

gistfile1.js

//Table component without shouldComponentUpdate

import React from 'react';
import _ from 'underscore';

export default React.createClass({
  getInitialState() {
    return {
      tableData: []
    };
  },

  componentWillMount() {
    // Generate initial table data state
    this.setState({
      tableData: _.range(0, 10).map(rowIndex => _.range(0, 10))
    });
  },

  onNewDataClick() {
    var tableData = this.state.tableData.map(row => {
      row[0] = Math.random();
      return row;
    });

    this.setState({
      tableData: tableData
    });
  },

  renderCellEl(content, index) {
    return (
      <td key={index}>{content}</td>
    );
  },

  renderRowEl(contentList, index) {
    return (
      <tr key={index}>{contentList.map(this.renderCellEl)}</tr>
    );
  },

  render() {
    return (
      <div>
        <table>
          {this.state.tableData.map(this.renderRowEl)}
        </table>
        <button onClick={this.onNewDataClick}>New data plskthnxbye</button>
      </div>
    );
  }
});

React's report on DOM updates done

0".0.0.0.$0.$0""set textContent""{"textContent":"0.40472540468908846"}"
1".0.0.0.$1.$0""set textContent""{"textContent":"0.4246360862161964"}"
2".0.0.0.$2.$0""set textContent""{"textContent":"0.038479496724903584"}"
3".0.0.0.$3.$0""set textContent""{"textContent":"0.6841884981840849"}"
4".0.0.0.$4.$0""set textContent""{"textContent":"0.6603023638017476"}"
5".0.0.0.$5.$0""set textContent""{"textContent":"0.28145029209554195"}"
6".0.0.0.$6.$0""set textContent""{"textContent":"0.695664837025106"}"
7".0.0.0.$7.$0""set textContent""{"textContent":"0.889470687834546"}"
8".0.0.0.$8.$0""set textContent""{"textContent":"0.251313682179898"}"
9".0.0.0.$9.$0""set textContent""{"textContent":"0.4046918931417167"}"