Week 10 - React

Question 1

What is a react component?

Answer 1

a function or class that returns a react element that represents a piece of your user interface

Question 2

How do you define a function component in React?

Answer 2

Write a JS function with props as a parameter and the rendered react elements as a return
*name of the function needs to be capitalized

Question 3

How do you mount a component to the DOM?

Answer 3

Render method of ReactDom

Question 4

What are props in React?

Answer 4

props = properties
they are read-only objects used to pass data between react components

Question 5

How do you pass props to a component?

Answer 5

pass them in as an argument with the prop name = value

Question 6

How do you write JS expressions in JSX?

Answer 6

Surround it with curly braces

Question 7

How do you create a “class” component in react?

Answer 7

Class keyword with component name (capitalized), extend React.Component, and define render() method which will return a react element

Question 8

How do you access props in a class component?

Answer 8

this.props

Question 9

What is the purpose of state in react?

Answer 9

Represents data/information about the component’s current status/situation
allows us to manage changing data in our app

Question 10

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

Answer 10

Pass it as a prop of the react element

Question 11

What are controlled components?

Answer 11

an input form element whose value is controlled by React

Question 12

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

Answer 12

value and onChange

Question 13

What array method is commonly used to create a list of react elements?

Answer 13

array.map

Question 14

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

Answer 14

Ids from data as keys –> it’s a unique identifier

Question 15

What does express.static() return?

Answer 15

a function

Question 16

What is the local __dirname variable in a node.js module?

Answer 16

It’s a variable that returns the directory name of the current module

Question 17

What does the join() method of Node’s path module do?

Answer 17

Joins path segments together and then normalizes the resulting path

Question 18

What does fetch() return?

Answer 18

a promise that resolves to a response object

Question 19

What is the default request method used by fetch?

Answer 19

‘GET’

Question 20

How do you specify the request object (GET, POST, etc.) when calling fetch?

Answer 20

specify it in the init object that acts as a 2nd parameter –> if you want to request the method specifically…
- assign the specific method as a string in caps to the method property inside the object
- example: fetch(url, { method: ‘POST’ })