How to force rerender in React

In React, you can force a component to rerender by calling its setState method and passing it a new state object.

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

  incrementCount() {
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.incrementCount()}>Increment</button>
      </div>
    );
  }
}

In this example, we define a MyComponent class with a count state property that is initially set to 0. The incrementCount method updates the count property by calling the setState method with a new state object that increments the count value by 1. The render method displays the current count value and a button that calls the incrementCount method when clicked.

When the user clicks the button, the incrementCount method is called, which updates the count state property and triggers a rerender of the component, updating the displayed count value.

ForceUpdate method

Alternatively, you can use the forceUpdate method to force a component to rerender without changing its state. However, it is generally recommended to update a component’s state instead of using forceUpdate if possible, as updating the state will automatically trigger a rerender and keep the component’s internal state in sync with the rendered output.

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

  incrementCount() {
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => {
          this.incrementCount();
          this.forceUpdate();
        }}>Increment and force update</button>
      </div>
    );
  }
}

In this example, we call forceUpdate after calling incrementCount to force a rerender of the component. However, we still update the count state property first to keep the component’s internal state in sync with the rendered output.

Key Takeaways

• To force a component to rerender in React, you can call its setState method and pass it a new state object.
• Alternatively, you can use the forceUpdate method to force a component to rerender without changing its state.
• It is generally recommended to update a component’s state instead of using forceUpdate if possible, as updating the state will automatically trigger a rerender and keep the component’s internal state in sync with the rendered output.

FAQ

What is setState in React?

setState is a method that is used to update the state of a React component.

What is forceUpdate in React?

forceUpdate is a method that is used to force a React component to rerender.

When should I use setState and when should I use forceUpdate?

It is generally recommended to use setState to update the state of a React component, as this will automatically trigger a rerender and keep the component’s internal state in sync with the rendered output. However, you can use forceUpdate to force a rerender of a component without changing its state. This can be useful in certain situations, such as when you need to update the rendered output without changing the component’s internal state.