When you declare a component as a function or a class, it must never modify its own props.
Let us take a below capital function,
function capital(amount, interest) {
return amount + interest;
}The above function is called “pure” because it does not attempt to change their inputs, and always return the same result for the same inputs. Hence, React has a single rule saying "All React components must act like pure functions with respect to their props."
