Mohammad FaisalTo read more articles like this, visit my blog
React is very unopinionated about how things should be structured. This is exactly why it’s our responsibility to keep our projects clean and maintainable.
Today, we will discuss some best practices to improve your React application’s health. These rules are widely accepted. As such, having this knowledge is imperative.
Everything will be shown with code, so buckle up!
1. Use JSX ShortHand
Try to use JSX shorthand for passing boolean variables. Let’s say you want to control the title visibility of a Navbar component.
Bad
return (
<Navbar showTitle={true} />
);
Good
return(
<Navbar showTitle />
)
2. Use Ternary Operators
Let’s say you want to show a user’s details based on role.
Bad
const { role } = user;
if(role === ADMIN) {
return <AdminUser />
}else{
return <NormalUser />
}
Good
const { role } = user;
return role === ADMIN ? <AdminUser /> : <NormalUser />
3. Take Advantage of Object Literals
Object literals can help make our code more readable. Let’s say you want to show three types of users based on their roles. You can’t use ternary because the number of options exceeds two.
Bad
const {role} = user
switch(role){
case ADMIN:
return <AdminUser />
case EMPLOYEE:
return <EmployeeUser />
case USER:
return <NormalUser />
}
Good
const {role} = user
const components = {
ADMIN: AdminUser,
EMPLOYEE: EmployeeUser,
USER: NormalUser
};
const Component = components[role];
return <Componenent />;
It looks much better now.
4. Use Fragments
Always use Fragment over Div. It keeps the code clean and is also beneficial for performance because one less node is created in the virtual DOM.
Bad
return (
<div>
<Component1 />
<Component2 />
<Component3 />
</div>
)
Good
return (
<>
<Component1 />
<Component2 />
<Component3 />
</>
)
5. Don't Define a Function Inside Render
Don’t define a function inside render. Try to keep the logic inside render to an absolute minimum.
Bad
return (
<button onClick={() => dispatch(ACTION_TO_SEND_DATA)}> // NOTICE HERE
This is a bad example
</button>
)
Good
const submitData = () => dispatch(ACTION_TO_SEND_DATA)
return (
<button onClick={submitData}>
This is a good example
</button>
)
6. Use Memo
React.PureComponent and Memo can significantly improve the performance of your application. They help us to avoid unnecessary rendering.
Bad
import React, { useState } from "react";
export const TestMemo = () => {
const [userName, setUserName] = useState("faisal");
const [count, setCount] = useState(0);
const increment = () => setCount((count) => count + 1);
return (
<>
<ChildrenComponent userName={userName} />
<button onClick={increment}> Increment </button>
</>
);
};
const ChildrenComponent =({ userName }) => {
console.log("rendered", userName);
return <div> {userName} </div>;
};
Although the child component should render only once because the value of count has nothing to do with the ChildComponent . But, it renders each time you click on the button.
Good
Let’s edit the ChildrenComponent to this:
import React ,{useState} from "react";
const ChildrenComponent = React.memo(({userName}) => {
console.log('rendered')
return <div> {userName}</div>
})
Now, no matter how many times you click on the button, it will render only when necessary.
7. Put CSS in JavaScript
Avoid raw JavaScript when writing React applications because organizing CSS is far harder than organizing JS.
Bad
// CSS FILE
.body {
height: 10px;
}
//JSX
return <div className='body'>
</div>
Good
const bodyStyle = {
height: "10px"
}
return <div style={bodyStyle}>
</div>
8. Use Object Destructuring
Use object destructuring to your advantage. Let’s say you need to show a user’s details.
Bad
return (
<>
<div> {user.name} </div>
<div> {user.age} </div>
<div> {user.profession} </div>
</>
)
Good
const { name, age, profession } = user;
return (
<>
<div> {name} </div>
<div> {age} </div>
<div> {profession} </div>
</>
)
9. String Props Don’t Need Curly Braces
When passing string props to a children component.
Bad
return(
<Navbar title={"My Special App"} />
)
Good
return(
<Navbar title="My Special App" />
)
10. Remove JS Code From JSX
Move any JS code out of JSX if that doesn’t serve any purpose of rendering or UI functionality.
Bad
return (
<ul>
{posts.map((post) => (
<li onClick={event => {
console.log(event.target, 'clicked!'); // <- THIS IS BAD
}} key={post.id}>{post.title}
</li>
))}
</ul>
);
Good
const onClickHandler = (event) => {
console.log(event.target, 'clicked!');
}
return (
<ul>
{posts.map((post) => (
<li onClick={onClickHandler} key={post.id}> {post.title} </li>
))}
</ul>
);
11. Use Template Literals
Use template literals to build large strings. Avoid using string concatenation. It’s nice and clean.
Bad
const userDetails = user.name + "'s profession is" + user.proffession
return (
<div> {userDetails} </div>
)
Good
const userDetails = `${user.name}'s profession is ${user.proffession}`
return (
<div> {userDetails} </div>
)
12. Import in Order
Always try to import things in a certain order. It improves code readability.
Bad
import React from 'react';
import ErrorImg from '../../assets/images/error.png';
import styled from 'styled-components/native';
import colors from '../../styles/colors';
import { PropTypes } from 'prop-types';
Good
The rule of thumb is to keep the import order like this:
Built-in
External
Internal
So the example above becomes:
import React from 'react';
import { PropTypes } from 'prop-types';
import styled from 'styled-components/native';
import ErrorImg from '../../assets/images/error.png';
import colors from '../../styles/colors';
13. Use Implicit return
Use the JavaScript feature implicit return in writing beautiful code. Let’s say your function does a simple calculation and returns the result.
Bad
const add = (a, b) => {
return a + b;
}
Good
const add = (a, b) => a + b;
14. Component Naming
Always use PascalCase for components and camelCase for instances.
Bad
import reservationCard from './ReservationCard';
const ReservationItem = <ReservationCard />;
Good
import ReservationCard from './ReservationCard';
const reservationItem = <ReservationCard />;
15. Reserved Prop Naming
Don’t use DOM component prop names for passing props between components because others might not expect these names.
Bad
<MyComponent style="dark" />
<MyComponent className="dark" />
Good
<MyComponent variant="fancy" />
16. Quotes
Use double quotes for JSX attributes and single quotes for all other JS.
Bad
<Foo bar='bar' />
<Foo style={{ left: "20px" }} />
Good
<Foo bar="bar" />
<Foo style={{ left: '20px' }} />
17. Prop Naming
Always use camelCase for prop names or PascalCase if the prop value is a React component.
Bad
<Component
UserName="hello"
phone_number={12345678}
/>
Good
<MyComponent
userName="hello"
phoneNumber={12345678}
Component={SomeComponent}
/>
18. JSX in Parentheses
If your component spans more than one line, always wrap it in parentheses.
Bad
return <MyComponent variant="long">
<MyChild />
</MyComponent>;
Good
return (
<MyComponent variant="long">
<MyChild />
</MyComponent>
);
19. Self-Closing Tags
If your component doesn’t have any children, then use self-closing tags. It improves readability.
Bad
<SomeComponent variant="stuff"></SomeComponent>
Good
<SomeComponent variant="stuff" />
20. Underscore in Method Name
Do not use underscores in any internal React method.
Bad
const _onClickHandler = () => {
// do stuff
}
Good
const onClickHandler = () => {
// do stuff
}
21. Alt Prop
Always include an alt prop in your <img > tags. And don’t use picture or image in your alt property because the screenreaders already announce img elements as images. No need to include that.
Bad
<img src="hello.jpg" />
<img src="hello.jpg" alt="Picture of me rowing a boat" />
Good
<img src="hello.jpg" alt="Me waving hello" />
Conclusion
There you go. Congratulations if you’ve made it this far! I hope you learned a thing or two from this article.
I hope you have a wonderful day! :D
Have something to say?
Resources
- Airbnb Guideline: https://github.com/airbnb/javascript/tree/master/react
Get in touch with me via LinkedIn or my Personal Website.
