useRenderCount

About

A simple debugging hook that tracks how many times a component has rendered. Useful for identifying unnecessary re-renders and optimizing component performance.

Examples

Basic example

import { useRenderCount } from "rooks";

export default function App() {
  const renderCount = useRenderCount();

  return (
    <div>
      <h1>Component Render Count</h1>
      <p>This component has rendered {renderCount} times</p>
    </div>
  );
}

Debugging unnecessary re-renders

import { useState } from "react";
import { useRenderCount } from "rooks";

export default function App() {
  const [count, setCount] = useState(0);
  const [name, setName] = useState("");
  const renderCount = useRenderCount();

  return (
    <div>
      <h1>Debugging Re-renders</h1>
      <p>Render count: {renderCount}</p>
      
      <div>
        <label>Counter: {count}</label>
        <button onClick={() => setCount(c => c + 1)}>Increment</button>
      </div>
      
      <div>
        <label>Name:</label>
        <input 
          value={name} 
          onChange={(e) => setName(e.target.value)}
          placeholder="Type your name"
        />
      </div>
      
      {renderCount > 10 && (
        <div style={{color: 'red'}}>
          Warning: This component has re-rendered {renderCount} times!
        </div>
      )}
    </div>
  );
}

Conditional behavior based on render count

import { useState, useEffect } from "react";
import { useRenderCount } from "rooks";

export default function App() {
  const [data, setData] = useState(null);
  const renderCount = useRenderCount();

  // Only show loading indicator after first render
  const showLoading = renderCount === 1 && !data;

  useEffect(() => {
    // Simulate data loading
    const timer = setTimeout(() => {
      setData("Data loaded successfully!");
    }, 2000);

    return () => clearTimeout(timer);
  }, []);

  return (
    <div>
      <h1>Conditional Rendering Example</h1>
      <p>Render #{renderCount}</p>
      
      {showLoading && <p>Loading...</p>}
      {data && <p>{data}</p>}
      
      <button onClick={() => setData(null)}>Reset Data</button>
    </div>
  );
}

Arguments

This hook does not accept any arguments.

Returns

Return value	Type	Description
renderCount	Number	The number of times the component has rendered (starts from 1)

Use Cases

Performance Debugging: Identify components that re-render too frequently
Development Tools: Build custom debugging components that show render information
Conditional Logic: Execute code only after a certain number of renders
Testing: Verify that optimizations are working correctly
Component Analysis: Understand how state changes affect component rendering

Notes

The render count starts from 1 (not 0) on the first render
Each call to the hook maintains its own independent render count
The count persists for the lifetime of the component
This hook is primarily intended for development and debugging purposes

useRenderCount

On this page