LargeSubtree() — react Function Reference

Architecture documentation for the LargeSubtree() function in LargeSubtree.js from the react codebase.

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BabelCompiler→ Validation→ LargeSubtree() — react Function Reference

Dependency Diagram

graph TD
  68441a8a_2dac_7bb9_951c_1ee57c1b0453["LargeSubtree()"]
  aa439c83_a130_686b_6832_de19aa600273["LargeSubtree.js"]
  68441a8a_2dac_7bb9_951c_1ee57c1b0453 -->|defined in| aa439c83_a130_686b_6832_de19aa600273
  style 68441a8a_2dac_7bb9_951c_1ee57c1b0453 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/react-devtools-shell/src/perf-regression/apps/LargeSubtree.js lines 18–44

export default function LargeSubtree(): React.Node {
  const [showList, setShowList] = React.useState(false);
  const toggleList = () => {
    const startTime = performance.now();
    setShowList(!showList);
    // requestAnimationFrame should happen after render+commit is done
    window.requestAnimationFrame(() => {
      const afterRenderTime = performance.now();
      console.log(
        `Time spent on ${showList ? 'unmounting' : 'mounting'} the subtree: ${
          afterRenderTime - startTime
        }ms`,
      );
    });
  };
  return (
    <div>
      <h2>Mount/Unmount a large subtree</h2>
      <p>Click the button to toggle the state. Open console for results.</p>
      <button onClick={toggleList}>toggle</button>
      <ul>
        <li key="dummy">dummy item</li>
        {showList && arr.map((num, idx) => <li key={idx}>{num}</li>)}
      </ul>
    </div>
  );
}