React TypeScript Part 2
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Learn the basics of TypeScript and how to use TypeScript in a React component
React Hooks Handbook
1
Intro to React Hooks
3:39
2
Create your first React app
4:23
3
React Component
2:54
4
Styling in React
5:06
5
Styles and Props
2:22
6
Understanding Hooks
3:21
7
useState Hook
2:54
8
useEffect Hook
3:41
9
useRef Hook
3:00
10
Props
3:11
11
Conditional Rendering
4:21
12
Load Local Data
4:04
13
Fetch Data from an API
5:40
14
Toggle a state
4:05
15
useInput Hook
6:04
16
Gatsby and React
6:44
17
NextJS and React
5:24
18
React TypeScript Part 1
8:19
19
React TypeScript Part 2
7:35
20
useScrollPosition Hook
4:26
21
useOnScreen hook
8:08
22
useContext Hook
8:32
23
Fragments
2:43
24
Lazy Loading
4:05
25
React Suspense
3:13
26
Environment Variables
4:43
27
Reach Router
5:31
28
URL Params
4:04
29
SEO and Metadata
6:47
30
Favicon
3:03
31
Dynamic Favicon
2:14
32
PropTypes
3:54
33
Custom PropTypes
3:58
34
useMemo Hook
4:05
35
forwardRef Hook
3:28
36
Handling Events
5:44
37
Spread attributes
3:35
38
useMousePosition Hook
4:55
39
useReducer with useContext Part 1
7:33
40
useReducer with useContext Part 2
6:48
41
useReducer with useContext Part 3
5:43
42
Netlify
5:08
43
Gatsby Cloud
6:19
44
Gatsby Plugin Image
8:11
45
useOnClickOutside Hook
6:32
46
useWindowSize Hook
4:14
47
usePageBottom hook
4:48
48
useLocalStorage Hook
5:27
49
Three.js in React Part 1
17:33
50
Three.js in React Part 2
11:18
TypeScript Basics
Basic function
If we create a basic function addNumbers in a TypeScript file (with a .ts extension), like on the image below, we'll see the variables x and y underlined. The warning message is Parameter 'y' implicitly has an 'any' type, but a better type may be inferred from usage. That is TypeScript complaining that we didn't provide a type for each argument passed in the function.
To fix this error, we can provide a type for each of the variables that we pass. In this case, x and y are both numbers. So let's add number as their type. This will fix the warning message.
TypeScript also makes sure that we pass in the correct number of arguments in each of our functions. If we only pass one number in the addNumbers function above, it'll raise an error, telling us that the addNumbers function requires two arguments, but we only provided one.
User object
Let's see how TypeScript will prevent errors when we're trying to access key-value pairs in an object. Let's create a User object, with the keys name, age and profession.
const user = {
name: "John",
age: 33,
profression: "Web Developer"
}If we're trying to access the user's location, TypeScript will raise an error that location doesn't exist on the user object we created: That prevents any error in development and also in the future, when the app will be released. However, if we do keep this code, it will return us undefined.
These are just simple examples of how TypeScript can make your life easier as a developer, because it checks for errors before you even see them! If you wish to learn more in-depth about TypeScript and all its basics, you can read the official documentation. Next, we'll learn how to use TypeScript in our Gatsby application, and create a component that will require props.
How to use TypeScript with Gatsby
Create a Gatsby project, and make sure that TypeScript is enabled in your project. Then, we'll create a new file in the src > components folder. Let's call it welcomeCard.tsx. In this file, paste the following code. This WelcomeCard component takes a name as a props, and we'll display this name on the card.
import React from "react"
const WelcomeCard = (name) => {
return (
<div>Welcome, {name}!</div>
)
}
export default WelcomeCardSince we're using TypeScript, the name argument passed to the component is underlined - if you remember correctly, we need to provide a type for each argument we pass into a function.
So let's provide the type for the name argument. It'll be a string.
// welcomeCard.tsx
import React from "react"
const WelcomeCard = (name: string) => {
return (
<div>Welcome, {name}!</div>
)
}
export default WelcomeCardIf you pass multiple props to your component, one option will be to write them all inside the parentheses, along with their type. However, we can create an interface called Props and write all the props inside of it. It'll make the code cleaner and easier to read.
// welcomeCard.tsx
interface Props {
name: string
age: number
profession: string
location: string
}Put the interface just before your define your WelcomeCard function. Interfaces are objects with keys. For each key, you need to provide its type. You can read more about Object types here.
Inside the parentheses of the WelcomeCard, we'll replace the arguments with the following. This tells the program that the WelcomeCard requires props, and the props are defined in the Props interface.
// welcomeCard.tsx
const WelcomeCard = (props: Props) => {
return (
<div>Welcome, {name}!</div>
)
}To access these props, we just need to add the following line of code.
// welcomeCard.tsx
const WelcomeCard = (props: Props) => {
const { name, age, profession, location } = props // Access the props with this line of code
return (
<div>Welcome, {name}! You are {age} years old, work as a {profession} and live in {location}.</div>
)
} To use the WelcomeCard component, you can import it and pass in the props as usual.
// index.tsx
import * as React from "react"
import WelcomeCard from "../components/welcomeCard"
const IndexPage = () => (
<div>
<WelcomeCard name="John" age={33} profession="Web developer" location="New York"/>
</div>
)
export default IndexPageBelow is the final code for the WelcomeCard, along with styling using styled-components.
// welcomeCard.tsx
import React from "react"
import styled from "styled-components"
interface Props {
name: string
age: number
profession: string
location: string
}
const WelcomeCard = (props: Props) => {
const { name, age, profession, location } = props
return (
<Wrapper>
<Title>Welcome, {name}!</Title>
<Paragraph>You are {age} years old, work as a {profession} and live in {location}.</Paragraph>
</Wrapper>
)
}
export default WelcomeCard
const Wrapper = styled.div`
text-align: center;
max-width: 375px;
padding: 20px;
background: rgba(40, 27, 90, 0.2);
border: 1px solid rgba(255, 255, 255, 0.3);
backdrop-filter: blur(40px);
/* Note: backdrop-filter has minimal browser support */
border-radius: 30px;
display: grid;
gap: 8px;
`
const Title = styled.h1`
font-weight: bold;
font-size: 24px;
line-height: 34px;
color: rgba(255,255,255,0.7);
`
const Paragraph = styled.p`
font-size: 16px;
font-style: normal;
font-weight: normal;
line-height: 22px;
letter-spacing: -0.078px;
color: #FFFFFF;
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react-hooks-handbook-react-typescript-part-2
1
Intro to React Hooks
An overview of React Hooks and the frameworks you can use to build your React application blazingly fast
3:39
2
Create your first React app
Create your first React project from the Terminal and save it on your local computer
4:23
3
React Component
Create your first JSX component using React
2:54
4
Styling in React
How to style your React components using inline styling, separate stylesheets or styled-components
5:06
5
Styles and Props
Render different styles depending on different properties passed to your component
2:22
6
Understanding Hooks
Learn about the basics of React Hooks, which introduced at React Conf 2018
3:21
7
useState Hook
Use the useState hook to manage local state in your React component
2:54
8
useEffect Hook
Manage with your component's lifecycle with the useEffect hook
3:41
9
useRef Hook
Learn about the useRef hook, which replaces the JavaScript getElementById way
3:00
10
Props
Learn about props in React to pass data from parent to child components
3:11
11
Conditional Rendering
Render different UIs depending on different conditions and states
4:21
12
Load Local Data
Load local JSON data into your React application
4:04
13
Fetch Data from an API
Learn the basics of asynchronous functions and promises by fetching data from an API using fetch, useEffect and useState
5:40
14
Toggle a state
Learn how to toggle a state from true to false and back again
4:05
15
useInput Hook
Create a hook to get the value and the onChange event of input fields
6:04
16
Gatsby and React
Create a static content-oriented website using React on Gatsby
6:44
17
NextJS and React
Create your first NextJS React application
5:24
18
React TypeScript Part 1
Learn how to create a React TypeScript application using the Create React App, Gatsby and NextJS methods
8:19
19
React TypeScript Part 2
Learn the basics of TypeScript and how to use TypeScript in a React component
7:35
20
useScrollPosition Hook
Create a custom hook to listen to the current window position of the user
4:26
21
useOnScreen hook
Create a custom hook to listen to when an element is visible on screen
8:08
22
useContext Hook
Manage global states throughout the entire application
8:32
23
Fragments
Group multiple children together with React Fragments
2:43
24
Lazy Loading
Lazy Load heavy components to improve performance
4:05
25
React Suspense
Wait for data with React Suspense and React.lazy
3:13
26
Environment Variables
Make environment variables secret with a .env file
4:43
27
Reach Router
Create a multiple-pages React application with Reach Router
5:31
28
URL Params
Create unique URL with URL Params
4:04
29
SEO and Metadata
Optimize a React application for search engines with React Helmet
6:47
30
Favicon
Add an icon to a React website
3:03
31
Dynamic Favicon
Change the favicon's fill color depending on the user's system appearance
2:14
32
PropTypes
Implement props type-checking with PropTypes
3:54
33
Custom PropTypes
Create a custom PropType using a validator function
3:58
34
useMemo Hook
Prevent unnecessary re-renders when the component stays the same
4:05
35
forwardRef Hook
Forward a ref to a child component
3:28
36
Handling Events
How to handle events in React
5:44
37
Spread attributes
Learn how to make use of the spread operator
3:35
38
useMousePosition Hook
Detect the user's mouse position on a bound element
4:55
39
useReducer with useContext Part 1
Create a reducer to be used in a context
7:33
40
useReducer with useContext Part 2
Incorporate useReducer with useContext
6:48
41
useReducer with useContext Part 3
Connect the context and reducer with the frontend
5:43
42
Netlify
Deploy to production using Netlify
5:08
43
Gatsby Cloud
Deploy to production using Gatsby Cloud
6:19
44
Gatsby Plugin Image
Use gatsby-plugin-image for automatic image resizing, formatting, and higher performance
8:11
45
useOnClickOutside Hook
Toggle a modal visibility with a useOnClickOutside hook
6:32
46
useWindowSize Hook
Create a hook to determine the width and height of the window
4:14
47
usePageBottom hook
Detect if the user scrolled to the bottom of the page
4:48
48
useLocalStorage Hook
Store an item in a browser's local storage
5:27
49
Three.js in React Part 1
Bring your website to life with beautiful 3D objects
17:33
50
Three.js in React Part 2
Bring your website to life with beautiful 3D objects
11:18
Meet the instructor
We all try to be consistent with our way of teaching step-by-step, providing source files and prioritizing design in our courses.
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iOS and Web developer
Developing web and mobile applications while learning new techniques everyday
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SwiftUI Advanced Handbook
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