One Way Data Binding

In React, the data flow is typically one-way, which means that changes to the state of a component are propagated down to its children via props, but not back up to the parent. This is often referred to as "one-way data binding".

When a component's state changes in React, the new state is passed down to its child components via props. The child components can then use these props to update their own state or render their content. However, any changes made to the child component's state don't automatically propagate back up to the parent component. Instead, if the child component needs to update the parent's state, it must do so by calling a function that was passed down as a prop.

This one-way data flow makes it easier to reason about the behavior of React components, since you can always trace the flow of data from the top-level component down to its children. It also makes it easier to write reusable components, since they can be composed together in different ways without introducing unexpected side effects.

However, there are cases where you may need to use two-way data binding in React. This can be accomplished by passing down a function as a prop that updates the parent's state based on the child's state, and calling that function from the child component's event handlers. This can be a useful technique for handling forms or other interactive elements where you need to synchronize the state of the parent and child components.