Q1. How react works?

Ans: React is a Javascript Library. In essence, it keeps a tree for us. On the nodes, this tree can perform efficient diff computations. Considering our HTML code to be a tree. That is, in fact, how the browser handles your DOM. React allows us to essentially re-construct our DOM in JavaScript and only push the changes that have actually occurred to the DOM. The render() method in React components takes input data and returns what should be displayed. It use the JSX syntax, which is similar to XML. This is how render() gets access to input data supplied into the component using .props.

Q2. Props vs State

Ans:
1. Props allow components to receive data from the outside world, whereas state allows them to produce and maintain their own data.
2. Props can only be passed from parent to child component where state can be defined in its own component
3. Property data is read-only and cannot be changed by a component that receives it from the outside where State data is editable by its own component, but it is kept private
4. Props are used to send data around, whereas state is used to keep track of it.

Q3. How useState works?

Ans: useState is a Hook that enables state variables to be used in functional components. This function takes the starting state and returns a variable with the current state value and another function to update it. We can add state to function components using useState. When you use useState inside a function component, it creates a single piece of state for that component. It returns an array with the state variable as the first element and a function to update the variable's value as the second element