Make React useEffect hook not run on initial render

🌟 Stop useEffect from Running on Initial Render in React

Are you struggling to make the useEffect hook in React not run on the initial render? We've got you covered! 🙌

The Issue 🤔

By default, the useEffect hook in React runs after every render, including the initial one. However, you may encounter situations where you want to skip the initial render and only execute the useEffect callback function for subsequent renders.

The Solution 💡

To make useEffect not run on the initial render, you can employ a simple workaround using an additional variable. Let's dive into the code example you provided to clarify the solution. 👇

function ComponentDidUpdateFunction() {
  const [count, setCount] = React.useState(0);

  React.useEffect(() => {
    // This callback function will run after each render, but we don't want it to run on the initial render.
    // The solution involves using an additional variable to check if it's the first render or not.
    if (count > 0) {
      console.log("componentDidUpdateFunction");
    }
  }, [count]);

  return (
    <div>
      <p>componentDidUpdateFunction: {count} times</p>
      <button
        onClick={() => {
          setCount(count + 1);
        }}
      >
        Click Me
      </button>
    </div>
  );
}

In the code above, we added the condition if (count > 0). By checking if the count value is greater than zero, we ensure that the useEffect callback function is only executed after the initial render.

Here's the updated example with the solution implemented:

class ComponentDidUpdateClass extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0,
    };
  }

  componentDidUpdate() {
    if (this.state.count > 0) {
      console.log("componentDidUpdateClass");
    }
  }

  render() {
    return (
      <div>
        <p>componentDidUpdateClass: {this.state.count} times</p>
        <button
          onClick={() => {
            this.setState({ count: this.state.count + 1 });
          }}
        >
          Click Me
        </button>
      </div>
    );
  }
}

The Result 🎉

Now, when you run your React application, you should see that the useEffect hook no longer executes the callback function during the initial render. Instead, it runs after each subsequent render, just like the componentDidUpdate lifecycle method in class components.

Your Turn! 🚀

Now that you've learned how to make useEffect skip the initial render, go ahead and apply this technique to your React projects. Let your components manage those side effects gracefully, while keeping your initial renders clean. Share your experiences and join the conversation in the comments below! 🗣️

Keep coding, and may the React hooks be ever in your favor! 😉