React

Question 1

What is React?

Answer 1

JavaScript library. Its aim is to allow developers to easily create fast user interfaces for websites and applications alike.

Question 2

What is a react element?

Answer 2

It is an object representation of a virtual DOM node.

Question 3

How do you mount a React element to the DOM?

Answer 3

render()

Question 4

What is JSX?

Answer 4

a syntax extension to Javascript

Question 5

Why must the React object be imported when authoring JSX in a module?

Question 6

How can you make Webpack and Babel work together to convert JSX into valid JavaScript?

Question 7

What is a React component?

Answer 7

A re-useable UI elements for a React app. It lets you combine your markup, CSS, and JavaScript.

Question 8

How do you define a function component in React?

Answer 8

function name() {
return (content in here);
}

Question 9

How do you mount a component to the DOM?

Answer 9

root.render(

<component></component>

);

Question 10

What are props in React?

Question 11

How do you pass props to a component?

Answer 11

as an argument

Question 12

How do you write JavaScript expressions in JSX?

Answer 12

{ content }

Question 13

What is the purpose of state in React?

Answer 13

It is essentially a components storage.

Question 14

How do you pass an event handler to a React element?

Question 15

What is a React Effect?

Question 16

When should you use an Effect and when should you not use an Effect?

Question 17

When do effects run?

Answer 17

they run at the end of the render.

Question 18

What function is used to decalre an Effect?

Answer 18

useEffect (callback function and array dependency

Question 19

What are Effect dependencies and how do you declare them?

Question 20

How do you cleanup from an Effect?