Your password bar goes from "weak" to "strong" when you add characters. Have you ever wondered how React 'remembers' your inputs? 'State' is your answer. A state remembers what input you added. Assume you are typing your name "John", initial state is the blank slate (starting value, like empty input, counter at zero, or an empty whiteboard) in the input bar, whenever you add a new letter, a function named 'setState' is called to change the state from "" (empty input bar) to "J", then again to "Jo", again to "Joh", etc... And following the setState, React automatically re-renders the UI.
Think of re-rendering as erasing everything and re-writing the UI with the new state. Initial state was "", then setState updates it from "" to "J". Following that, React automatically erases the first UI and then it will build a new UI with the new state.
Why not just use a variable?
You might be thinking, "Why don't just use variables and change them whenever you want it?", and you might do that, but the value only changes in your codebase, but the UI will still show the first value. (and that defeated the purpose)
What is [state, setState] concept?
