REACT

Question 1

What is React?

Answer 1

a JS library/framework for building user interfaces

Question 2

What is a React element?

Answer 2

a JavaScript Object that describe what a DOM element should loop like

Question 3

How do you mount a React element to the DOM?

Answer 3

calling root.render(element)

Question 4

what is the difference between a library and a framework

Answer 4

inversion of control

Question 5

What is Babel?

Answer 5

a javascript compiler that can convert modern JS or other plugins to something more backwards compatible

Question 6

What is a Plug-in?

Answer 6

external software add-ons that help customize stuff

Question 7

What is a Webpack loader?

Answer 7

it runs through code and turns it into backwards compatible JS before sending it to Webpack

Question 8

How can you make Babel and Webpack work together?

Answer 8

by downloading babel-loader from NPM

Question 9

What is JSX?

Answer 9

a syntax extension for JS to work with REACT to help structure the UI

Question 10

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

Answer 10

because JSX produces REACT elements

Question 11

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

Answer 11

with architecture plugins

Question 12

What is a React component?

Answer 12

a function or class that returns or defines a react element

Question 13

How do you define a function component in React?

Answer 13

function Name(props) {
    return 
}

Question 14

How do you mount a component to the DOM?

Answer 14

query for an anchor point, assign it as a root of ReactDOM,

call root.render() and pass as the argument

Question 15

What are props in React?

Answer 15

objects

arbitrary imputs(arguments) for react components

Question 16

How do you pass props to a component?

Answer 16

by defining them as a key: value pair inside the react element

Question 17

How do you write JavaScript expressions in JSX?

Answer 17

inside curly braces

Question 18

How do you create “class” component in React?

Answer 18

class ‘name’ extends React.component {
prototypes
}

Question 19

How do you access props in a class component?

Answer 19

this.prop.name

Question 20

What is the purpose of state in React?

Answer 20

to track changes over time

Question 21

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

Question 22

What are controlled components?

Answer 22

an input form element who’s value is controlled by React

Question 23

What two props must you pass to an input for it to be “controlled”?

Answer 23

value and onChange handler

Question 24

What Array method is commonly used to create a list of React elements?

Answer 24

map

Question 25

What is the best value to use as a “key” prop when rendering lists?

Answer 25

a unique identifier

Question 26

When does React call a component’s component.didMount method?

Answer 26

immediately after the component is rendered into the DOM tree

Question 27

Name three React. Component lifecycle methods.

Answer 27

component. didMount(), component.didUpdate(),

component. willUnmount()

Question 28

How do you pass data to a child component?

Answer 28

as a prop