easyFrontend Developer interview question

In React, what is the difference between props and state?

What the interviewer wants to hear

Props are passed from parent and are read-only in the child
State is owned and updated by the component itself
Changing state or receiving new props triggers a re-render
Lift state up when several components need it
Data flows one way, from parent to child

Model answer

Props are inputs a parent passes to a child component, like function arguments. The child must treat them as read-only. State is data a component owns and can change over time, usually with useState or useReducer. When state changes, or when a parent passes new props, React re-renders the component. Data in React flows one way, from parent to child. If two siblings need the same data, I lift the state up to their closest common parent and pass it down as props, along with a callback so the child can ask the parent to update it. A good rule is to keep state as small as possible and derive everything else during render.

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In React, what is the difference between props and state?

What the interviewer wants to hear

Model answer

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