What are the scenarios where React re-renders the page?

There are several situations in which React re-renders the page.

1. Initial rendering: When the page is first loaded, React performs the initial rendering by constructing the DOM tree based on the initial state of the components.
2. Component Updates: React will re-render components when the state or props of a component change. This can be triggered using the setState() method.
3. Parent component updates: when the parent component is re-rendered, its child components will also be re-rendered as a result.
4. Context change: When using the Context feature in React, if the value of the context changes, the respective components will be re-rendered.
5. Forced re-render: by using the forceUpdate() method, React will forcibly re-render the component even if its state has not changed.
6. When you use the ReactDOM.render() method, React will re-render the entire application.

It is important to note that React aims to minimize DOM manipulations for better performance. Therefore, it does not always re-render the entire page but rather compares the virtual DOM and only updates the parts that have changed.