There are four different phases of React component’s lifecycle:

Initialization: In this phase react component prepares setting up the initial state and default props.

Mounting: The react component is ready to mount in the browser DOM. This phase covers componentWillMount and componentDidMount lifecycle methods.

Updating: In this phase, the component get updated in two ways, sending the new props and updating the state. This phase covers shouldComponentUpdate, componentWillUpdate and componentDidUpdate lifecycle methods.

Unmounting: In this last phase, the component is not needed and get unmounted from the browser DOM. This phase include componentWillUnmount lifecycle method.