In 2018 React introduced Hooks. "They let you use state and other React features without writing a class." Hooks can be used in functional components but a lot of projects are still written in class components.
In this serie I'll explain how easy it is to convert/refactor your class component to a functional component so you can use Hooks.
States
class component
import React from 'react';
import {Button} from "react-bootstrap";
class Example extends React.Component {
constructor(props) {
super(props);
this.state = {
show: false
}
this.handleShow = this.handleShow.bind(this);
}
handleShow() {
this.setState({show: true});
}
render() {
const {show} = this.state;
return (
<>
<Button onClick={this.handleShow}>Show</Button>
{show && <h1>Awesome</h1>}
</>
)
}
}
export default Example;
functional component
const Example = () => {
const [show, setShow] = useState(false);
const handleShow = () => {
setShow(true);
}
return (
<>
<Button onClick={handleShow}>Show</Button>
{show && <h1>Awesome<h1>}
</>
);
}
1. Extends
Functional components no longer need to extends from React.Component
2. Constructor
Where as a constructor is needed in a class component to set states, a functional component can use the "useState" hook. Just import this hook to use it import React, {useState} from 'react';
3. Passing Functions to Components
In class components it is necessary to pass functions to components in the constructor by .bind(this)
in order to work. Not needed in a functional component anymore.
4. Function
Functions are written a little different. The good old myFunction() { ... }
has been replaced by myFunction = () => { ... }
5. Variables
Not needed anymore to point out to this.state.myState
, but just use myState
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