Interview Q&A / React

1. What is the difference between state and props in React?

   Props are inputs passed into a component by its parent and are read-only inside it. State is data a component owns and can change over time, and changing it makes the component re-render.

   BeginnerIn-depth3 min read
2. What is the difference between function components and class components, and which should you use today?

   Function components are plain functions that use hooks for state and lifecycle behaviour. Class components use this.state and lifecycle methods. New code should use function components; classes still work, and error boundaries still need a class.

   BeginnerQuick answer1 min read
3. Why must React component names start with a capital letter?

   JSX treats lowercase tags like div as built-in DOM elements and capitalised names like Card as variables that refer to components. A lowercase component name gets rendered as an unknown HTML tag instead.

   BeginnerQuick answer1 min read