Example of how to use react-addons-perf in tests

ReactPerfTester.js

/* eslint-disable no-console */
import Perf from 'react-addons-perf';
import sinon from 'sinon';

/**
 * Counts the number of DOM operations that occurred while executing `fn`.
 *
 * Example usage:
 #   import React from 'react';
 #   import ReactDOM from 'react-dom';
 #   const node = document.createElement('div');
 #   const component = ReactDOM.render(<div><span>abc</span><span>def</span></div>, node);
 #   const opsCount = getDOMOpsCount(() => {
 #     ReactDOM.render(<div><span>ghi</span><span>jkl</span></div>, node);
 #   });
 *   console.log(opsCount); // 2
 *
 * @param  {Function} fn function that renders a component into a DOM node with React
 * @return {Number}      number of DOM operations
 */
export function getDOMOpsCount(fn) {
  const oldTable = console.table;
  console.table = sinon.stub();
  try {
    Perf.start();
    fn();
    Perf.stop();
    Perf.printDOM();
    sinon.assert.calledOnce(console.table); // printDOM calls `console.table(results)`
    return console.table.getCall(0).args[0].length;
  } finally {
    console.table = oldTable;
  }
}