What are props in reactjs?

A key concept in ReactJS is props, short for properties, which allows components to communicate with each other. Props are read-only inputs passed from a parent component to a child component. These inputs can be anything from simple values like strings or numbers to complex objects or even functions.

The important thing to remember about props is that they are immutable; once a prop has been passed to a child component, the child component cannot alter it in any way.

Props are primarily used for passing data down from the parent component to its children. The children then process this data to render a view or make it interactive.

For example, you might have a button component that requires a label to display itself. In your parent component, you would pass the button a "label" prop with the desired label text. This way, the button component remains flexible and reusable, capable of displaying any label passed to it.

Another important role props play is in maintaining a unidirectional data flow in React, meaning data always flows one way, from parent to child. This makes the application easier to debug and reason about, as the data flow remains consistent and predictable.

Additionally, because props are read-only, components do not change any value passed as props, ensuring that they render the same way whenever they receive the same props.

In simple terms, props are the way data is sent and received between parent and child components in React. They are immutable, encourage one-way data flow, and are essential for building reusable and predictable components within a React application.