React

Question 1

What is Webpack?

Answer 1

a tool that bundles your javascript files/modules

Question 2

How do you add a devDependency to a package?

Answer 2

install –save-dev

Question 3

What is an NPM script?

Answer 3

a command that you can use to execute multiple command line commands

Question 4

How do you execute Webpack with npm run?

Answer 4

npm run webpack

Question 5

How are ES Modules different from CommonJS modules?

Answer 5

more compact, different syntax …

Question 6

What kind of modules can Webpack support?

Answer 6

.

Question 7

What is a React element?

Answer 7

an object

Question 8

How do you mount a React element to the DOM?

Answer 8

ReactDOM.render(…)

Question 9

What is Babel?

Answer 9

a toolchain used to convert ES6 code to older versions of it

Question 10

What is a Plug-in?

Answer 10

adds a feature to an existing program

Question 11

What is a Webpack loader?

Answer 11

transformations that allow you to pre-process files as you import(load) them

Question 12

How can you make Babel and Webpack work together?

Answer 12

babel loader

Question 13

What is JSX?

Answer 13

Syntax extension to JavaScript. Allows you to write HTML expressions in React

Question 14

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

Answer 14

it is not in the native library.

JSX compiles to calls of the createElement method

Question 15

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

Answer 15

need to install the babel transform-react-jsx plugin

Question 16

What is a React component?

Answer 16

javascript function that is independent and reusable - returns a react element

Question 17

How do you define a function component in React?

Answer 17

just write a function that accepts a props parameter and returns a react object - must start with Capital letter

Question 18

How do you mount a component to the DOM?

Answer 18

ReactDOM.render()

Question 19

What are props in React?

Answer 19

custom inputs you can pass into react functions (properties)

Question 20

How do you pass props to a component?

Answer 20

when defining the react element, add an attribute to it - ex:

Question 21

How do you write JavaScript expressions in JSX?

Answer 21

inside curly braces

Question 22

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

Answer 22

map()

Question 23

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

Answer 23

something from the dataset that gives it a unique identifier amongst the list item’s siblings

Question 24

How do you create “class” component in React?

Answer 24

use: extends React.Component

Question 25

How do you access props in a class component?

Answer 25

this.props

Question 26

What is the purpose of state in React?

Answer 26

keeps track of changes over the passage of time

the component will re-render when state is changed

Question 27

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

Answer 27

define it in when creating the react element as a prop