When should you use props and when should you use state?

Question

React

When should you use props and when should you use state?

Answer 1

read-only props - parameters passed from <MyElement param1={param1} param2={param2} />
state the current state of the element, which we can overwrite at any time inside the element

Answer 2

State is the internal mutable state of the component, props is the external "immutable" data that is passed through the parent
"immutable" is more of a wish than an axiom

Answer 3

When to use state
In short, most of your components are stateless. There is a controller-view pattern: you usually have a few controller components at the top levels of the tree that have their own state, and the rest of the components just accept props and render them.