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React Hooks for Developers

Hooks allow functional components to have state and other React features without writing classes. Specifically, the useState hook enables functional components to have local state by calling useState and setting an initial state value. For example, a counter component can use useState to track a count value and update it by calling the setter function returned from useState. This avoids the need for class components when managing local state.

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Sagir Rahman
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57 views9 pages

React Hooks for Developers

Hooks allow functional components to have state and other React features without writing classes. Specifically, the useState hook enables functional components to have local state by calling useState and setting an initial state value. For example, a counter component can use useState to track a count value and update it by calling the setter function returned from useState. This avoids the need for class components when managing local state.

Uploaded by

Sagir Rahman
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as ODP, PDF, TXT or read online on Scribd
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Introduction to React Hooks

Giving superpowers to functional


components
From React’s version 16.8.0, Hooks are
introduced to make functional components
more useful.
Class Vs Function

In React, class components are stateful and


smart, being state is attached to it and kept
persistent through renders. Then functional
components were stateless and dumb
components, having nor state nor logic
attached to it. state in it, and just used to break
down complex components into segments.
Class Vs Function

As an example, class component can have


state, and it could be manipulated using
lifecycle methods such as constructor,
componentDidMount and such. However,
functional component only accepts props from
its parent, and renders accordingly. It wouldn’t
keep internal state value, that would be
persistent through renders, but rather renders
according to whatever passed through props
Class Vs Function

In complex React application, there is parent


class component keeping track of state, and
manipulate state according to business logic.
Afterwards child functional components are
passed props, and used only for rendering
purpose. These wouldn’t have any persistent
state in it, and just used to break down complex
components into segments.
Like

<DigitalWatch>
Parent class component with state, and
business logic to count time.
→ <TimeView time={this.state.time}>
Child functional component only with props and
just rendering props.
Hooks

React Hooks enable functional components to


attach local state with it, and React will
preserve this state between re-renders.
Thereby this will allow React to be used without
classes.
●
However, we often can’t break complex
components down any further because the logic
is stateful and can’t be extracted to a function or
another component.
Hooks

Let's get started with hooks


state Hook

import React, { useState } from 'react';function Example() {


const [count, setCount] = useState(0);return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}> Add </button>
<button onClick={() => setCount(count - 1)}> Remove </button>
</div>
);
}

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