Should all React component props always be readonly in Typescript?

Question

It seems like they should be since props should never be changed within the component. I can't find any answers on Google or Stack Overflow so asking here just to be sure.

Answer 1

It's not a Typescript specificity but a React one.

React is design to render component according a set of props. If you want to change the way a component is render the parent need to generate new props and give it to the children.

The React data flow is a one-way flow from parents to children. You can't and you don't want to mutate a props coming from a parents. Because if props can be mutated it should produce UI issues with React component life cycle. A component re-render only if the reference of one of his props change. Mutate a props will not re-render component and your UI will be different from your data.