Which kinds of initialization is more appropriate in constructor vs componentWillMount?

Which kinds of initialization is more appropriate in constructor vs componentWillMount?

If you have a React component that requires some setup, such as timers or the WebAudio API, you might be unsure about whether the initialization should go in the constructor or the componentWillMount method. In this blog post, we will explore the advantages and disadvantages of each approach to help you make an informed decision.

The Constructor

The constructor is typically used to assign the initial state of a stateful component using this.state. Apart from that, it is recommended to avoid performing any other actions within the constructor. Doing so helps keep the codebase clean and follows best practices.

constructor(props) {
  super(props);
  this.state = {
    // initial state assignment
  };
}

The componentWillMount Method

The componentWillMount method is often considered unnecessary and, in most cases, an anti-pattern. One common reason developers use this method is to update the state from an external source right before rendering. However, assigning the state in the constructor achieves the same result.

componentWillMount() {
  // unnecessary use of componentWillMount
  this.setState({
    // state assignment
  });
}

It is important to note that you can use setState inside the componentWillMount method but not within the constructor.

Handling Side Effects

For handling side effects, such as data fetching or DOM manipulation, it is recommended to use the componentDidMount method. This method is called immediately after the component is mounted and provides a suitable place to perform such actions.

componentDidMount() {
  // perform side effects here
}

Flux Actions

If you need to call a Flux action, particularly for making AJAX calls, you can use either the componentWillMount or componentDidMount methods. However, it is preferable to use componentDidMount for consistency and to ensure that all other initializations have completed before making the AJAX call.

Conclusion

In summary, it is generally recommended to assign initial state in the constructor and avoid using the componentWillMount method for such purposes. For handling side effects, utilize the componentDidMount method, and if you require Flux actions, prefer componentDidMount over componentWillMount for consistency.

By understanding the differences between the constructor and componentWillMount and their appropriate use cases, you can write clean and efficient code in your React components.

reference :

https://stackoverflow.com/questions/38137740/which-kinds-of-initialization-is-more-appropriate-in-constructor-vs-componentwil

Read Another Article :

reactjs