Amit Garu
5 years ago
commit
3730393ec8
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<div align="center">
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<h1> 30 Days Of React: Statet</h1>
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<a class="header-badge" target="_blank" href="https://www.linkedin.com/in/asabeneh/">
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<img src="https://img.shields.io/badge/style--5eba00.svg?label=LinkedIn&logo=linkedin&style=social">
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</a>
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<a class="header-badge" target="_blank" href="https://twitter.com/Asabeneh">
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<img alt="Twitter Follow" src="https://img.shields.io/twitter/follow/asabeneh?style=social">
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</a>
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<sub>Author:
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<a href="https://www.linkedin.com/in/asabeneh/" target="_blank">Asabeneh Yetayeh</a><br>
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<small> October, 2020</small>
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</sub>
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</div>
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[<< Day 7](../07_Day_Class_Components/07_class_components.md) | [Day 9 >>](../09_Day_Conditional_Rendering/09_conditional_rendering.md)
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- [State](#state)
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- [What is State?](#what-is-state)
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- [How to set a state](#how-to-set-a-state)
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- [Resetting a state using a JavaScript method](#resetting-a-state-using-a-javascript-method)
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- [Exercises](#exercises)
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- [Exercises: Level 1](#exercises-level-1)
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- [Exercises: Level 2](#exercises-level-2)
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- [Exercises: Level 3](#exercises-level-3)
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# State
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## What is State?
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What is state ? The English meaning of state is _the particular condition that someone or something is in at a specific time_.
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Let us see some states being something - Are you happy or sad? - Is light on or off ? Is present or absent ? - Is full or empty ? For instance, I am happy because I am enjoying creating 30 Days Of React challenge. I believe that you are happy too.
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State is an object in react which let the component re-render when state data changes.
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## How to set a state
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We set an initial state inside the constructor or outside the constructor of a class based component. We do not directly change or mutate the state but we use the _setState()_ method to reset to a new state. . As you can see below in the state object we have count with initial value 0. We can access the state object using _this.state_ and the property name. See the example below.
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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class App extends React.Component {
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// declaring state
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state = {
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count: 0,
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}
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render() {
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// accessing the state value
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const count = this.state.count
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return (
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<div className='App'>
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<h1>{count} </h1>
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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If you run the above code you will see zero on the browser. We can increase or decrease the value the state by changing the value of the state using JavaScript method.
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## Resetting a state using a JavaScript method
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Now, let's add some methods which increase or decrease the value of count by clicking a button. Let us add a button to increase and a button to decrease the value of count. To set the state we use react method _this.setState_. See the example below
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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class App extends React.Component {
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// declaring state
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state = {
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count: 0,
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}
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render() {
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// accessing the state value
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const count = this.state.count
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return (
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<div className='App'>
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<h1>{count} </h1>
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<button onClick={() => this.setState({ count: this.state.count + 1 })}>
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Add One
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</button>
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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If you understand the above example, adding minus one method will be easy. Let us add the minus one method on the click event.
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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class App extends React.Component {
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// declaring state
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state = {
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count: 0,
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}
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render() {
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// accessing the state value
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const count = this.state.count
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return (
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<div className='App'>
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<h1>{count} </h1>
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<div>
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<button
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onClick={() => this.setState({ count: this.state.count + 1 })}
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>
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Add One
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</button>{' '}
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<button
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onClick={() => this.setState({ count: this.state.count - 1 })}
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>
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Minus One
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</button>
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</div>
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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Both button work well, but we need to re-structure the code well. Let us create separate methods in the component.
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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class App extends React.Component {
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// declaring state
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state = {
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count: 0,
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}
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// method which add one to the state
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addOne = () => {
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this.setState({ count: this.state.count + 1 })
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}
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// method which subtract one to the state
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minusOne = () => {
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this.setState({ count: this.state.count - 1 })
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}
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render() {
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// accessing the state value
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const count = this.state.count
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return (
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<div className='App'>
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<h1>{count} </h1>
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<div>
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<button className='btn btn-add' onClick={this.addOne}>
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+1
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</button>{' '}
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<button className='btn btn-minus' onClick={this.minusOne}>
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-1
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</button>
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</div>
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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Let us do more example about state, in the following example we will develop small application which shows either a dog or cat.
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We can start by setting the initial state with cat then when it is clicked it will show dog and alternatively. We need one method which changes the animal alternatively. See the code below. If you want to see live click [here](https://codepen.io/Asabeneh/full/LYVxKpq).
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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class App extends React.Component {
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// declaring state
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state = {
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image: 'https://www.smithsstationah.com/imagebank/eVetSites/Feline/01.jpg',
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}
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changeAnimal = () => {
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let dogURL =
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'https://static.onecms.io/wp-content/uploads/sites/12/2015/04/dogs-pembroke-welsh-corgi-400x400.jpg'
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let catURL =
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'https://www.smithsstationah.com/imagebank/eVetSites/Feline/01.jpg'
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let image = this.state.image === catURL ? dogURL : catURL
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this.setState({ image })
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}
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render() {
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// accessing the state value
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const count = this.state.count
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return (
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<div className='App'>
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<h1>30 Days Of React</h1>
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<div className='animal'>
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<img src={this.state.image} alt='animal' />
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</div>
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<button onClick={this.changeAnimal} class='btn btn-add'>
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Change
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</button>
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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Now, let's put all the codes we have so far and also let's implement state when it is necessary.
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```js
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// index.js
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import React from 'react'
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import ReactDOM from 'react-dom'
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import asabenehImage from './images/asabeneh.jpg'
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// Fuction to show month date year
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const showDate = (time) => {
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const months = [
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'January',
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'February',
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'March',
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'April',
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'May',
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'June',
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'July',
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'August',
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'September',
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'October',
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'November',
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'December',
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]
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const month = months[time.getMonth()].slice(0, 3)
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const year = time.getFullYear()
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const date = time.getDate()
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return ` ${month} ${date}, ${year}`
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}
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// User Card Component
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const UserCard = ({ user: { firstName, lastName, image } }) => (
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<div className='user-card'>
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<img src={image} alt={firstName} />
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<h2>
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{firstName}
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{lastName}
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</h2>
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</div>
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)
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// A button component
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const Button = ({ text, onClick, style }) => (
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<button style={style} onClick={onClick}>
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{text}
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</button>
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)
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// CSS styles in JavaScript Object
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const buttonStyles = {
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backgroundColor: '#61dbfb',
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padding: 10,
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border: 'none',
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borderRadius: 5,
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margin: 3,
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cursor: 'pointer',
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fontSize: 18,
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color: 'white',
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}
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// class based component
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class Header extends React.Component {
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constructor(props) {
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super(props)
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// the code inside the constructor run before any other code
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}
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render() {
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console.log(this.props.data)
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const {
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welcome,
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title,
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subtitle,
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author: { firstName, lastName },
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date,
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} = this.props.data
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return (
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<header style={this.props.styles}>
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<div className='header-wrapper'>
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<h1>{welcome}</h1>
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<h2>{title}</h2>
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<h3>{subtitle}</h3>
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<p>
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{firstName} {lastName}
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</p>
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<small>{date}</small>
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</div>
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</header>
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)
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}
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}
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const Count = ({ count, addOne, minusOne }) => (
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<div>
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<h1>{count} </h1>
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<div>
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<Button text='+1' onClick={addOne} style={buttonStyles} />
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<Button text='-1' onClick={minusOne} style={buttonStyles} />
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</div>
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</div>
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)
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// TechList Component
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// class base component
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class TechList extends React.Component {
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constructor(props) {
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super(props)
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}
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render() {
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const { techs } = this.props
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const techsFormatted = techs.map((tech) => <li key={tech}>{tech}</li>)
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return techsFormatted
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}
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}
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// Main Component
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// Class Component
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class Main extends React.Component {
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constructor(props) {
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super(props)
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}
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render() {
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const {
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techs,
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user,
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greetPeople,
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handleTime,
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changeBackground,
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count,
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addOne,
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minusOne,
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} = this.props
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return (
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<main>
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<div className='main-wrapper'>
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<p>Prerequisite to get started react.js:</p>
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<ul>
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<TechList techs={techs} />
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</ul>
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<UserCard user={user} />
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<Button
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text='Greet People'
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onClick={greetPeople}
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style={buttonStyles}
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/>
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<Button text='Show Time' onClick={handleTime} style={buttonStyles} />
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<Button
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text='Change Background'
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onClick={changeBackground}
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style={buttonStyles}
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/>
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<Count count={count} addOne={addOne} minusOne={minusOne} />
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</div>
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</main>
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)
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}
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}
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// Footer Component
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// Class component
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class Footer extends React.Component {
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constructor(props) {
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super(props)
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}
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render() {
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return (
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<footer>
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<div className='footer-wrapper'>
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<p>Copyright {this.props.date.getFullYear()}</p>
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</div>
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</footer>
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)
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}
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}
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class App extends React.Component {
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state = {
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count: 0,
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styles: {
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backgroundColor: '',
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color: '',
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},
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}
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showDate = (time) => {
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const months = [
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'January',
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'February',
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'March',
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'April',
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'May',
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'June',
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'July',
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'August',
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'September',
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'October',
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'November',
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'December',
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]
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const month = months[time.getMonth()].slice(0, 3)
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const year = time.getFullYear()
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const date = time.getDate()
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return ` ${month} ${date}, ${year}`
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}
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addOne = () => {
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this.setState({ count: this.state.count + 1 })
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}
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// method which subtract one to the state
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minusOne = () => {
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this.setState({ count: this.state.count - 1 })
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}
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handleTime = () => {
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alert(this.showDate(new Date()))
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}
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greetPeople = () => {
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alert('Welcome to 30 Days Of React Challenge, 2020')
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}
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changeBackground = () => {}
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render() {
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const data = {
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welcome: 'Welcome to 30 Days Of React',
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title: 'Getting Started React',
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subtitle: 'JavaScript Library',
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author: {
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firstName: 'Asabeneh',
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lastName: 'Yetayeh',
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},
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date: 'Oct 7, 2020',
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}
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const techs = ['HTML', 'CSS', 'JavaScript']
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const date = new Date()
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// copying the author from data object to user variable using spread operator
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const user = { ...data.author, image: asabenehImage }
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return (
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<div className='app'>
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{this.state.backgroundColor}
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<Header data={data} />
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<Main
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user={user}
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techs={techs}
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handleTime={this.handleTime}
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greetPeople={this.greetPeople}
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changeBackground={this.changeBackground}
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addOne={this.addOne}
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minusOne={this.minusOne}
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count={this.state.count}
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/>
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<Footer date={new Date()} />
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</div>
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)
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}
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}
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const rootElement = document.getElementById('root')
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ReactDOM.render(<App />, rootElement)
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```
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I believe that now you have a very good understanding of state. After this, we will use state in other sections too because state and props is the core of a react application.
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## Exercises
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### Exercises: Level 1
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1. What was your state today? Are you happy? I hope so. If you manage to make it this far you should be happy.
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2. What is state in React ?
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3. What is the difference between props and state in React ?
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||||
4. How do you access state in a React component ?
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||||
5. How do you set a set in a React component ?
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||||
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||||
### Exercises: Level 2
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||||
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1. Use React state to change the background of the page. You can use this technique to apply a dark mode for your portfolio.
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||||
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||||
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||||
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2. After long time of lock down you may think of travelling and you do not know where to go. Then make use of this random country selector to select your holiday destination.
|
||||
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||||
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### Exercises: Level 3
|
||||
|
||||
Coming
|
||||
|
||||
🎉 CONGRATULATIONS ! 🎉
|
||||
|
||||
[<< Day 7](../07_Day_Class_Components/07_class_components.md) | [Day 9 >>](../09_Day_Conditional_Rendering/09_conditional_rendering.md)
|
||||
@ -0,0 +1,23 @@
|
||||
# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
|
||||
|
||||
# dependencies
|
||||
/node_modules
|
||||
/.pnp
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||||
.pnp.js
|
||||
|
||||
# testing
|
||||
/coverage
|
||||
|
||||
# production
|
||||
/build
|
||||
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||||
# misc
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||||
.DS_Store
|
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.env.local
|
||||
.env.development.local
|
||||
.env.test.local
|
||||
.env.production.local
|
||||
|
||||
npm-debug.log*
|
||||
yarn-debug.log*
|
||||
yarn-error.log*
|
||||
@ -0,0 +1,5 @@
|
||||
# 30 Days of React App: Day 3
|
||||
|
||||
In the project directory, you can run to start the project
|
||||
|
||||
### `npm start`
|
||||
@ -0,0 +1,34 @@
|
||||
{
|
||||
"name": "30-days-of-react",
|
||||
"version": "0.1.0",
|
||||
"private": true,
|
||||
"dependencies": {
|
||||
"@testing-library/jest-dom": "^4.2.4",
|
||||
"@testing-library/react": "^9.3.2",
|
||||
"@testing-library/user-event": "^7.1.2",
|
||||
"react": "^16.13.1",
|
||||
"react-dom": "^16.13.1",
|
||||
"react-scripts": "3.4.3"
|
||||
},
|
||||
"scripts": {
|
||||
"start": "react-scripts start",
|
||||
"build": "react-scripts build",
|
||||
"test": "react-scripts test",
|
||||
"eject": "react-scripts eject"
|
||||
},
|
||||
"eslintConfig": {
|
||||
"extends": "react-app"
|
||||
},
|
||||
"browserslist": {
|
||||
"production": [
|
||||
">0.2%",
|
||||
"not dead",
|
||||
"not op_mini all"
|
||||
],
|
||||
"development": [
|
||||
"last 1 chrome version",
|
||||
"last 1 firefox version",
|
||||
"last 1 safari version"
|
||||
]
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,111 @@
|
||||
<!DOCTYPE html>
|
||||
<html lang="en">
|
||||
<head>
|
||||
<meta charset="utf-8" />
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1" />
|
||||
<link
|
||||
href="https://fonts.googleapis.com/css?family=Montserrat:300,400,500|Roboto:300,400,500&display=swap"
|
||||
rel="stylesheet"
|
||||
/>
|
||||
<meta
|
||||
name="description"
|
||||
content="Web site created using create-react-app"
|
||||
/>
|
||||
|
||||
<title>30 Days Of React App</title>
|
||||
<style>
|
||||
|
||||
/* == General style === */
|
||||
|
||||
* {
|
||||
box-sizing: border-box;
|
||||
padding: 0;
|
||||
margin: 0;
|
||||
}
|
||||
|
||||
html,
|
||||
body {
|
||||
height: 100%;
|
||||
line-height: 1.5;
|
||||
font-family: 'Montserrat';
|
||||
font-weight: 300;
|
||||
color: black;
|
||||
}
|
||||
|
||||
.root {
|
||||
min-height: 100%;
|
||||
position: relative;
|
||||
}
|
||||
|
||||
.header-wrapper,
|
||||
.main-wrapper,
|
||||
.footer-wrapper {
|
||||
width: 85%;
|
||||
margin: auto;
|
||||
}
|
||||
|
||||
.header-wrapper,
|
||||
.main-wrapper {
|
||||
padding: 10px;
|
||||
margin: 2px auto;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 70px;
|
||||
font-weight: 300;
|
||||
}
|
||||
|
||||
h2,
|
||||
h3 {
|
||||
font-weight: 300;
|
||||
}
|
||||
|
||||
header {
|
||||
background-color: #61dbfb;
|
||||
padding: 25;
|
||||
padding: 10px;
|
||||
}
|
||||
|
||||
main {
|
||||
padding: 10px;
|
||||
padding-bottom: 60px;
|
||||
/* Height of the footer */
|
||||
}
|
||||
|
||||
ul {
|
||||
margin-left: 15px;
|
||||
}
|
||||
|
||||
ul li {
|
||||
list-style: none;
|
||||
}
|
||||
|
||||
footer {
|
||||
position: absolute;
|
||||
bottom: 0;
|
||||
width: 100%;
|
||||
height: 60px;
|
||||
/* Height of the footer */
|
||||
background: #6cf;
|
||||
}
|
||||
|
||||
.footer-wrapper {
|
||||
font-weight: 400;
|
||||
text-align: center;
|
||||
line-height: 60px;
|
||||
}
|
||||
.user-card {
|
||||
margin-top: 10px;
|
||||
}
|
||||
.user-card > img {
|
||||
border-radius: 50%;
|
||||
width: 14%;
|
||||
}
|
||||
|
||||
</style>
|
||||
|
||||
</head>
|
||||
<body>
|
||||
<div id="root"></div>
|
||||
</body>
|
||||
</html>
|
||||
File diff suppressed because it is too large
Load Diff
@ -0,0 +1,13 @@
|
||||
export const tenHighestPopulation = [
|
||||
{ country: 'World', population: 7693165599 },
|
||||
{ country: 'China', population: 1377422166 },
|
||||
{ country: 'India', population: 1295210000 },
|
||||
{ country: 'United States of America', population: 323947000 },
|
||||
{ country: 'Indonesia', population: 258705000 },
|
||||
{ country: 'Brazil', population: 206135893 },
|
||||
{ country: 'Pakistan', population: 194125062 },
|
||||
{ country: 'Nigeria', population: 186988000 },
|
||||
{ country: 'Bangladesh', population: 161006790 },
|
||||
{ country: 'Russian Federation', population: 146599183 },
|
||||
{ country: 'Japan', population: 126960000 },
|
||||
]
|
||||
|
After Width: | Height: | Size: 20 KiB |
|
After Width: | Height: | Size: 82 KiB |
|
After Width: | Height: | Size: 18 KiB |
|
After Width: | Height: | Size: 12 KiB |
|
After Width: | Height: | Size: 40 KiB |
@ -0,0 +1,256 @@
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
import asabenehImage from './images/asabeneh.jpg'
|
||||
|
||||
// Fuction to show month date year
|
||||
|
||||
const showDate = (time) => {
|
||||
const months = [
|
||||
'January',
|
||||
'February',
|
||||
'March',
|
||||
'April',
|
||||
'May',
|
||||
'June',
|
||||
'July',
|
||||
'August',
|
||||
'September',
|
||||
'October',
|
||||
'November',
|
||||
'December',
|
||||
]
|
||||
|
||||
const month = months[time.getMonth()].slice(0, 3)
|
||||
const year = time.getFullYear()
|
||||
const date = time.getDate()
|
||||
return ` ${month} ${date}, ${year}`
|
||||
}
|
||||
|
||||
// User Card Component
|
||||
const UserCard = ({ user: { firstName, lastName, image } }) => (
|
||||
<div className='user-card'>
|
||||
<img src={image} alt={firstName} />
|
||||
<h2>
|
||||
{firstName}
|
||||
{lastName}
|
||||
</h2>
|
||||
</div>
|
||||
)
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 18,
|
||||
color: 'white',
|
||||
}
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
// the code inside the constructor run before any other code
|
||||
}
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const Count = ({ count, addOne, minusOne }) => (
|
||||
<div>
|
||||
<h1>{count} </h1>
|
||||
<div>
|
||||
<Button text='+1' onClick={addOne} style={buttonStyles} />
|
||||
<Button text='-1' onClick={minusOne} style={buttonStyles} />
|
||||
</div>
|
||||
</div>
|
||||
)
|
||||
|
||||
// TechList Component
|
||||
// class base component
|
||||
class TechList extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
}
|
||||
render() {
|
||||
const { techs } = this.props
|
||||
const techsFormatted = techs.map((tech) => <li key={tech}>{tech}</li>)
|
||||
return techsFormatted
|
||||
}
|
||||
}
|
||||
|
||||
// Main Component
|
||||
// Class Component
|
||||
class Main extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
}
|
||||
render() {
|
||||
const {
|
||||
techs,
|
||||
user,
|
||||
greetPeople,
|
||||
handleTime,
|
||||
changeBackground,
|
||||
count,
|
||||
addOne,
|
||||
minusOne,
|
||||
} = this.props
|
||||
return (
|
||||
<main>
|
||||
<div className='main-wrapper'>
|
||||
<p>Prerequisite to get started react.js:</p>
|
||||
<ul>
|
||||
<TechList techs={techs} />
|
||||
</ul>
|
||||
<UserCard user={user} />
|
||||
<Button
|
||||
text='Greet People'
|
||||
onClick={greetPeople}
|
||||
style={buttonStyles}
|
||||
/>
|
||||
<Button text='Show Time' onClick={handleTime} style={buttonStyles} />
|
||||
<Button
|
||||
text='Change Background'
|
||||
onClick={changeBackground}
|
||||
style={buttonStyles}
|
||||
/>
|
||||
<Count count={count} addOne={addOne} minusOne={minusOne} />
|
||||
</div>
|
||||
</main>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
// Footer Component
|
||||
// Class component
|
||||
class Footer extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
}
|
||||
render() {
|
||||
return (
|
||||
<footer>
|
||||
<div className='footer-wrapper'>
|
||||
<p>Copyright {this.props.date.getFullYear()}</p>
|
||||
</div>
|
||||
</footer>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
count: 0,
|
||||
styles: {
|
||||
backgroundColor: '',
|
||||
color: '',
|
||||
},
|
||||
}
|
||||
showDate = (time) => {
|
||||
const months = [
|
||||
'January',
|
||||
'February',
|
||||
'March',
|
||||
'April',
|
||||
'May',
|
||||
'June',
|
||||
'July',
|
||||
'August',
|
||||
'September',
|
||||
'October',
|
||||
'November',
|
||||
'December',
|
||||
]
|
||||
|
||||
const month = months[time.getMonth()].slice(0, 3)
|
||||
const year = time.getFullYear()
|
||||
const date = time.getDate()
|
||||
return ` ${month} ${date}, ${year}`
|
||||
}
|
||||
addOne = () => {
|
||||
this.setState({ count: this.state.count + 1 })
|
||||
}
|
||||
|
||||
// method which subtract one to the state
|
||||
minusOne = () => {
|
||||
this.setState({ count: this.state.count - 1 })
|
||||
}
|
||||
handleTime = () => {
|
||||
alert(this.showDate(new Date()))
|
||||
}
|
||||
greetPeople = () => {
|
||||
alert('Welcome to 30 Days Of React Challenge, 2020')
|
||||
}
|
||||
changeBackground = () => {}
|
||||
render() {
|
||||
const data = {
|
||||
welcome: 'Welcome to 30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 7, 2020',
|
||||
}
|
||||
const techs = ['HTML', 'CSS', 'JavaScript']
|
||||
const date = new Date()
|
||||
// copying the author from data object to user variable using spread operator
|
||||
const user = { ...data.author, image: asabenehImage }
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
<Main
|
||||
user={user}
|
||||
techs={techs}
|
||||
handleTime={this.handleTime}
|
||||
greetPeople={this.greetPeople}
|
||||
changeBackground={this.changeBackground}
|
||||
addOne={this.addOne}
|
||||
minusOne={this.minusOne}
|
||||
count={this.state.count}
|
||||
/>
|
||||
<Footer date={new Date()} />
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
File diff suppressed because it is too large
Load Diff
@ -0,0 +1,790 @@
|
||||
<div align="center">
|
||||
<h1> 30 Days Of React: Conditional Rendering</h1>
|
||||
<a class="header-badge" target="_blank" href="https://www.linkedin.com/in/asabeneh/">
|
||||
<img src="https://img.shields.io/badge/style--5eba00.svg?label=LinkedIn&logo=linkedin&style=social">
|
||||
</a>
|
||||
<a class="header-badge" target="_blank" href="https://twitter.com/Asabeneh">
|
||||
<img alt="Twitter Follow" src="https://img.shields.io/twitter/follow/asabeneh?style=social">
|
||||
</a>
|
||||
|
||||
<sub>Author:
|
||||
<a href="https://www.linkedin.com/in/asabeneh/" target="_blank">Asabeneh Yetayeh</a><br>
|
||||
<small> October, 2020</small>
|
||||
</sub>
|
||||
|
||||
</div>
|
||||
|
||||
[<< Day 8](../08_Day_States/08_states.md) | [Day 10 >>](../10_Day_Events/10_events.md)
|
||||
|
||||
|
||||
|
||||
# Conditional Rendering
|
||||
|
||||
As we can understand from the term, conditional rendering is a way to render different JSX or component at different condition. We can implement conditional rendering using regular if and else statement, ternary operator and &&. Let's implement a different conditional rendering.
|
||||
|
||||
## Conditional Rendering using If and Else statement
|
||||
|
||||
In the code below, we have an initial state of loggedIn which is false. If the state is false we inform user to log in otherwise we welcome the user.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
<p>Select a country for your next holiday</p>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 7, 2020',
|
||||
}
|
||||
|
||||
// conditional rendering using if and else statement
|
||||
|
||||
let status
|
||||
|
||||
if (this.state.loggedIn) {
|
||||
status = <h3>Welcome to 30 Days Of React</h3>
|
||||
} else {
|
||||
status = <h3>Please Login</h3>
|
||||
}
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
{status}
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
Let's add a method which allow as to toggle the status of the user. We should have a button to handle event for logging in and logging out.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
|
||||
let status
|
||||
let text
|
||||
|
||||
if (this.state.loggedIn) {
|
||||
status = <h1>Welcome to 30 Days Of React</h1>
|
||||
text = 'Logout'
|
||||
} else {
|
||||
status = <h3>Please Login</h3>
|
||||
text = 'Login'
|
||||
}
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
{status}
|
||||
<Button text={text} style={buttonStyles} onClick={this.handleLogin} />
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
How about if our condition is more than two? Like pure JavaScript we can use if else if statement. In general, conditional rendering is not different from pure JavaScript conditional statement.
|
||||
|
||||
## Conditional Rendering using Ternary Operator
|
||||
|
||||
Ternary operator is an an alternative for if else statement. However, there is more use cases for ternary operator than if else statement. For example, use can use ternary operator inside styles, className or many places in a component than regular if else statement.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
|
||||
let status = this.state.loggedIn ? (
|
||||
<h1>Welcome to 30 Days Of React</h1>
|
||||
) : (
|
||||
<h3>Please Login</h3>
|
||||
)
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
{status}
|
||||
<Button
|
||||
text={this.state.loggedIn ? 'Logout' : 'Login'}
|
||||
style={buttonStyles}
|
||||
onClick={this.handleLogin}
|
||||
/>
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
In addition to JSX, we can also conditionally render a component. Let's change the above conditional JSX to a component.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
|
||||
const Login = () => (
|
||||
<div>
|
||||
<h3>Please Login</h3>
|
||||
</div>
|
||||
)
|
||||
const Welcome = (props) => (
|
||||
<div>
|
||||
<h1>Welcome to 30 Days Of React</h1>
|
||||
</div>
|
||||
)
|
||||
|
||||
const status = this.state.loggedIn ? <Welcome /> : <Login />
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
{status}
|
||||
<Button
|
||||
text={this.state.loggedIn ? 'Logout' : 'Login'}
|
||||
style={buttonStyles}
|
||||
onClick={this.handleLogin}
|
||||
/>
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
## Conditional Rendering using && Operator
|
||||
|
||||
The && operator render the right JSX operand if the left operand(expression) is true.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
const Login = () => (
|
||||
<div>
|
||||
<h3>Please Login</h3>
|
||||
</div>
|
||||
)
|
||||
const Welcome = (props) => (
|
||||
<div>
|
||||
<h1>Welcome to 30 Days Of React</h1>
|
||||
</div>
|
||||
)
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
techs: ['HTML', 'CSS', 'JS'],
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
|
||||
const status = this.state.loggedIn ? <Welcome /> : <Login />
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
{status}
|
||||
<Button
|
||||
text={this.state.loggedIn ? 'Logout' : 'Login'}
|
||||
style={buttonStyles}
|
||||
onClick={this.handleLogin}
|
||||
/>
|
||||
{this.state.techs.length === 3 && (
|
||||
<p>You have all the prerequisite courses to get started React</p>
|
||||
)}
|
||||
{!this.state.loggedIn && (
|
||||
<p>
|
||||
Please login to access more information about 30 Days Of React
|
||||
challenge
|
||||
</p>
|
||||
)}
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
In the previous section, we used alert box to greet people and also to display time. Let's render the greeting and time on browser DOM instead of displaying on alert box.
|
||||
|
||||
```js
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const Message = ({ message }) => (
|
||||
<div>
|
||||
<h1>{message}</h1>
|
||||
</div>
|
||||
)
|
||||
const Login = () => (
|
||||
<div>
|
||||
<h3>Please Login</h3>
|
||||
</div>
|
||||
)
|
||||
const Welcome = (props) => (
|
||||
<div>
|
||||
<h1>Welcome to 30 Days Of React</h1>
|
||||
</div>
|
||||
)
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// TechList Component
|
||||
// class base component
|
||||
class TechList extends React.Component {
|
||||
render() {
|
||||
const { techs } = this.props
|
||||
const techsFormatted = techs.map((tech) => <li key={tech}>{tech}</li>)
|
||||
return techsFormatted
|
||||
}
|
||||
}
|
||||
|
||||
// Main Component
|
||||
// Class Component
|
||||
class Main extends React.Component {
|
||||
render() {
|
||||
const {
|
||||
techs,
|
||||
greetPeople,
|
||||
handleTime,
|
||||
loggedIn,
|
||||
handleLogin,
|
||||
message,
|
||||
} = this.props
|
||||
console.log(message)
|
||||
|
||||
const status = loggedIn ? <Welcome /> : <Login />
|
||||
return (
|
||||
<main>
|
||||
<div className='main-wrapper'>
|
||||
<p>Prerequisite to get started react.js:</p>
|
||||
<ul>
|
||||
<TechList techs={this.props.techs} />
|
||||
</ul>
|
||||
{techs.length === 3 && (
|
||||
<p>You have all the prerequisite courses to get started React</p>
|
||||
)}
|
||||
<div>
|
||||
<Button
|
||||
text='Show Time'
|
||||
onClick={handleTime}
|
||||
style={buttonStyles}
|
||||
/>{' '}
|
||||
<Button
|
||||
text='Greet People'
|
||||
onClick={greetPeople}
|
||||
style={buttonStyles}
|
||||
/>
|
||||
{!loggedIn && <p>Please login to access more information about 30 Days Of React challenge</p>}
|
||||
</div>
|
||||
<div style={{ margin: 30 }}>
|
||||
<Button
|
||||
text={loggedIn ? 'Logout' : 'Login'}
|
||||
style={buttonStyles}
|
||||
onClick={handleLogin}
|
||||
/>
|
||||
<br />
|
||||
{status}
|
||||
</div>
|
||||
<Message message={message} />
|
||||
</div>
|
||||
</main>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// Footer Component
|
||||
// Class component
|
||||
class Footer extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
}
|
||||
render() {
|
||||
return (
|
||||
<footer>
|
||||
<div className='footer-wrapper'>
|
||||
<p>Copyright {this.props.date.getFullYear()}</p>
|
||||
</div>
|
||||
</footer>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
techs: ['HTML', 'CSS', 'JS'],
|
||||
message: 'Click show time or Greet people to change me',
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
showDate = (time) => {
|
||||
const months = [
|
||||
'January',
|
||||
'February',
|
||||
'March',
|
||||
'April',
|
||||
'May',
|
||||
'June',
|
||||
'July',
|
||||
'August',
|
||||
'September',
|
||||
'October',
|
||||
'November',
|
||||
'December',
|
||||
]
|
||||
|
||||
const month = months[time.getMonth()].slice(0, 3)
|
||||
const year = time.getFullYear()
|
||||
const date = time.getDate()
|
||||
return `${month} ${date}, ${year}`
|
||||
}
|
||||
handleTime = () => {
|
||||
let message = this.showDate(new Date())
|
||||
this.setState({ message })
|
||||
}
|
||||
greetPeople = () => {
|
||||
let message = 'Welcome to 30 Days Of React Challenge, 2020'
|
||||
this.setState({ message })
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
const techs = ['HTML', 'CSS', 'JavaScript']
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
|
||||
<Main
|
||||
techs={techs}
|
||||
handleTime={this.handleTime}
|
||||
greetPeople={this.greetPeople}
|
||||
loggedIn={this.state.loggedIn}
|
||||
handleLogin={this.handleLogin}
|
||||
message={this.state.message}
|
||||
/>
|
||||
|
||||
<Footer date={new Date()} />
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
```
|
||||
|
||||
## Exercises
|
||||
|
||||
### Exercises: Level 1
|
||||
|
||||
1. What is conditional rendering?
|
||||
2. How do you implement conditional rendering?
|
||||
3. Which method of conditional rendering do you prefer?
|
||||
|
||||
### Exercises: Level 2
|
||||
|
||||
Coming
|
||||
|
||||
### Exercises: Level 3
|
||||
|
||||
Coming
|
||||
|
||||
🎉 CONGRATULATIONS ! 🎉
|
||||
|
||||
[<< Day 8](../08_Day_States/08_states.md) | [Day 10 >>](../10_Day_Events/10_events.md)
|
||||
@ -0,0 +1,23 @@
|
||||
# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
|
||||
|
||||
# dependencies
|
||||
/node_modules
|
||||
/.pnp
|
||||
.pnp.js
|
||||
|
||||
# testing
|
||||
/coverage
|
||||
|
||||
# production
|
||||
/build
|
||||
|
||||
# misc
|
||||
.DS_Store
|
||||
.env.local
|
||||
.env.development.local
|
||||
.env.test.local
|
||||
.env.production.local
|
||||
|
||||
npm-debug.log*
|
||||
yarn-debug.log*
|
||||
yarn-error.log*
|
||||
@ -0,0 +1,5 @@
|
||||
# 30 Days of React App: Day 3
|
||||
|
||||
In the project directory, you can run to start the project
|
||||
|
||||
### `npm start`
|
||||
@ -0,0 +1,34 @@
|
||||
{
|
||||
"name": "30-days-of-react",
|
||||
"version": "0.1.0",
|
||||
"private": true,
|
||||
"dependencies": {
|
||||
"@testing-library/jest-dom": "^4.2.4",
|
||||
"@testing-library/react": "^9.3.2",
|
||||
"@testing-library/user-event": "^7.1.2",
|
||||
"react": "^16.13.1",
|
||||
"react-dom": "^16.13.1",
|
||||
"react-scripts": "3.4.3"
|
||||
},
|
||||
"scripts": {
|
||||
"start": "react-scripts start",
|
||||
"build": "react-scripts build",
|
||||
"test": "react-scripts test",
|
||||
"eject": "react-scripts eject"
|
||||
},
|
||||
"eslintConfig": {
|
||||
"extends": "react-app"
|
||||
},
|
||||
"browserslist": {
|
||||
"production": [
|
||||
">0.2%",
|
||||
"not dead",
|
||||
"not op_mini all"
|
||||
],
|
||||
"development": [
|
||||
"last 1 chrome version",
|
||||
"last 1 firefox version",
|
||||
"last 1 safari version"
|
||||
]
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,111 @@
|
||||
<!DOCTYPE html>
|
||||
<html lang="en">
|
||||
<head>
|
||||
<meta charset="utf-8" />
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1" />
|
||||
<link
|
||||
href="https://fonts.googleapis.com/css?family=Montserrat:300,400,500|Roboto:300,400,500&display=swap"
|
||||
rel="stylesheet"
|
||||
/>
|
||||
<meta
|
||||
name="description"
|
||||
content="Web site created using create-react-app"
|
||||
/>
|
||||
|
||||
<title>30 Days Of React App</title>
|
||||
<style>
|
||||
|
||||
/* == General style === */
|
||||
|
||||
* {
|
||||
box-sizing: border-box;
|
||||
padding: 0;
|
||||
margin: 0;
|
||||
}
|
||||
|
||||
html,
|
||||
body {
|
||||
height: 100%;
|
||||
line-height: 1.5;
|
||||
font-family: 'Montserrat';
|
||||
font-weight: 300;
|
||||
color: black;
|
||||
}
|
||||
|
||||
.root {
|
||||
min-height: 100%;
|
||||
position: relative;
|
||||
}
|
||||
|
||||
.header-wrapper,
|
||||
.main-wrapper,
|
||||
.footer-wrapper {
|
||||
width: 85%;
|
||||
margin: auto;
|
||||
}
|
||||
|
||||
.header-wrapper,
|
||||
.main-wrapper {
|
||||
padding: 10px;
|
||||
margin: 2px auto;
|
||||
}
|
||||
|
||||
h1 {
|
||||
font-size: 70px;
|
||||
font-weight: 300;
|
||||
}
|
||||
|
||||
h2,
|
||||
h3 {
|
||||
font-weight: 300;
|
||||
}
|
||||
|
||||
header {
|
||||
background-color: #61dbfb;
|
||||
padding: 25;
|
||||
padding: 10px;
|
||||
}
|
||||
|
||||
main {
|
||||
padding: 10px;
|
||||
padding-bottom: 60px;
|
||||
/* Height of the footer */
|
||||
}
|
||||
|
||||
ul {
|
||||
margin-left: 15px;
|
||||
}
|
||||
|
||||
ul li {
|
||||
list-style: none;
|
||||
}
|
||||
|
||||
footer {
|
||||
position: absolute;
|
||||
bottom: 0;
|
||||
width: 100%;
|
||||
height: 60px;
|
||||
/* Height of the footer */
|
||||
background: #6cf;
|
||||
}
|
||||
|
||||
.footer-wrapper {
|
||||
font-weight: 400;
|
||||
text-align: center;
|
||||
line-height: 60px;
|
||||
}
|
||||
.user-card {
|
||||
margin-top: 10px;
|
||||
}
|
||||
.user-card > img {
|
||||
border-radius: 50%;
|
||||
width: 14%;
|
||||
}
|
||||
|
||||
</style>
|
||||
|
||||
</head>
|
||||
<body>
|
||||
<div id="root"></div>
|
||||
</body>
|
||||
</html>
|
||||
File diff suppressed because it is too large
Load Diff
@ -0,0 +1,13 @@
|
||||
export const tenHighestPopulation = [
|
||||
{ country: 'World', population: 7693165599 },
|
||||
{ country: 'China', population: 1377422166 },
|
||||
{ country: 'India', population: 1295210000 },
|
||||
{ country: 'United States of America', population: 323947000 },
|
||||
{ country: 'Indonesia', population: 258705000 },
|
||||
{ country: 'Brazil', population: 206135893 },
|
||||
{ country: 'Pakistan', population: 194125062 },
|
||||
{ country: 'Nigeria', population: 186988000 },
|
||||
{ country: 'Bangladesh', population: 161006790 },
|
||||
{ country: 'Russian Federation', population: 146599183 },
|
||||
{ country: 'Japan', population: 126960000 },
|
||||
]
|
||||
|
After Width: | Height: | Size: 20 KiB |
|
After Width: | Height: | Size: 82 KiB |
|
After Width: | Height: | Size: 18 KiB |
|
After Width: | Height: | Size: 12 KiB |
|
After Width: | Height: | Size: 40 KiB |
@ -0,0 +1,230 @@
|
||||
// index.js
|
||||
import React from 'react'
|
||||
import ReactDOM from 'react-dom'
|
||||
|
||||
// class based component
|
||||
class Header extends React.Component {
|
||||
render() {
|
||||
console.log(this.props.data)
|
||||
const {
|
||||
welcome,
|
||||
title,
|
||||
subtitle,
|
||||
author: { firstName, lastName },
|
||||
date,
|
||||
} = this.props.data
|
||||
|
||||
return (
|
||||
<header style={this.props.styles}>
|
||||
<div className='header-wrapper'>
|
||||
<h1>{welcome}</h1>
|
||||
<h2>{title}</h2>
|
||||
<h3>{subtitle}</h3>
|
||||
<p>
|
||||
{firstName} {lastName}
|
||||
</p>
|
||||
<small>{date}</small>
|
||||
</div>
|
||||
</header>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const Message = ({ message }) => (
|
||||
<div>
|
||||
<h1>{message}</h1>
|
||||
</div>
|
||||
)
|
||||
const Login = () => (
|
||||
<div>
|
||||
<h3>Please Login</h3>
|
||||
</div>
|
||||
)
|
||||
const Welcome = (props) => (
|
||||
<div>
|
||||
<h1>Welcome to 30 Days Of React</h1>
|
||||
</div>
|
||||
)
|
||||
|
||||
// A button component
|
||||
const Button = ({ text, onClick, style }) => (
|
||||
<button style={style} onClick={onClick}>
|
||||
{text}
|
||||
</button>
|
||||
)
|
||||
|
||||
// TechList Component
|
||||
// class base component
|
||||
class TechList extends React.Component {
|
||||
render() {
|
||||
const { techs } = this.props
|
||||
const techsFormatted = techs.map((tech) => <li key={tech}>{tech}</li>)
|
||||
return techsFormatted
|
||||
}
|
||||
}
|
||||
|
||||
// Main Component
|
||||
// Class Component
|
||||
class Main extends React.Component {
|
||||
render() {
|
||||
const {
|
||||
techs,
|
||||
greetPeople,
|
||||
handleTime,
|
||||
loggedIn,
|
||||
handleLogin,
|
||||
message,
|
||||
} = this.props
|
||||
console.log(message)
|
||||
|
||||
const status = loggedIn ? <Welcome /> : <Login />
|
||||
return (
|
||||
<main>
|
||||
<div className='main-wrapper'>
|
||||
<p>Prerequisite to get started react.js:</p>
|
||||
<ul>
|
||||
<TechList techs={this.props.techs} />
|
||||
</ul>
|
||||
{techs.length === 3 && (
|
||||
<p>You have all the prerequisite courses to get started React</p>
|
||||
)}
|
||||
<div>
|
||||
<Button
|
||||
text='Show Time'
|
||||
onClick={handleTime}
|
||||
style={buttonStyles}
|
||||
/>{' '}
|
||||
<Button
|
||||
text='Greet People'
|
||||
onClick={greetPeople}
|
||||
style={buttonStyles}
|
||||
/>
|
||||
{!loggedIn && (
|
||||
<p>
|
||||
Please login to access more information about 30 Days Of React
|
||||
challenge
|
||||
</p>
|
||||
)}
|
||||
</div>
|
||||
<div style={{ margin: 30 }}>
|
||||
<Button
|
||||
text={loggedIn ? 'Logout' : 'Login'}
|
||||
style={buttonStyles}
|
||||
onClick={handleLogin}
|
||||
/>
|
||||
<br />
|
||||
{status}
|
||||
</div>
|
||||
<Message message={message} />
|
||||
</div>
|
||||
</main>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
// CSS styles in JavaScript Object
|
||||
const buttonStyles = {
|
||||
backgroundColor: '#61dbfb',
|
||||
padding: 10,
|
||||
border: 'none',
|
||||
borderRadius: 5,
|
||||
margin: 3,
|
||||
cursor: 'pointer',
|
||||
fontSize: 22,
|
||||
color: 'white',
|
||||
margin: '0 auto',
|
||||
}
|
||||
|
||||
// Footer Component
|
||||
// Class component
|
||||
class Footer extends React.Component {
|
||||
constructor(props) {
|
||||
super(props)
|
||||
}
|
||||
render() {
|
||||
return (
|
||||
<footer>
|
||||
<div className='footer-wrapper'>
|
||||
<p>Copyright {this.props.date.getFullYear()}</p>
|
||||
</div>
|
||||
</footer>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
class App extends React.Component {
|
||||
state = {
|
||||
loggedIn: false,
|
||||
techs: ['HTML', 'CSS', 'JS'],
|
||||
message: 'Click show time or Greet people to change me',
|
||||
}
|
||||
handleLogin = () => {
|
||||
this.setState({
|
||||
loggedIn: !this.state.loggedIn,
|
||||
})
|
||||
}
|
||||
showDate = (time) => {
|
||||
const months = [
|
||||
'January',
|
||||
'February',
|
||||
'March',
|
||||
'April',
|
||||
'May',
|
||||
'June',
|
||||
'July',
|
||||
'August',
|
||||
'September',
|
||||
'October',
|
||||
'November',
|
||||
'December',
|
||||
]
|
||||
|
||||
const month = months[time.getMonth()].slice(0, 3)
|
||||
const year = time.getFullYear()
|
||||
const date = time.getDate()
|
||||
return `${month} ${date}, ${year}`
|
||||
}
|
||||
handleTime = () => {
|
||||
let message = this.showDate(new Date())
|
||||
this.setState({ message })
|
||||
}
|
||||
greetPeople = () => {
|
||||
let message = 'Welcome to 30 Days Of React Challenge, 2020'
|
||||
this.setState({ message })
|
||||
}
|
||||
|
||||
render() {
|
||||
const data = {
|
||||
welcome: '30 Days Of React',
|
||||
title: 'Getting Started React',
|
||||
subtitle: 'JavaScript Library',
|
||||
author: {
|
||||
firstName: 'Asabeneh',
|
||||
lastName: 'Yetayeh',
|
||||
},
|
||||
date: 'Oct 9, 2020',
|
||||
}
|
||||
const techs = ['HTML', 'CSS', 'JavaScript']
|
||||
|
||||
return (
|
||||
<div className='app'>
|
||||
{this.state.backgroundColor}
|
||||
<Header data={data} />
|
||||
|
||||
<Main
|
||||
techs={techs}
|
||||
handleTime={this.handleTime}
|
||||
greetPeople={this.greetPeople}
|
||||
loggedIn={this.state.loggedIn}
|
||||
handleLogin={this.handleLogin}
|
||||
message={this.state.message}
|
||||
/>
|
||||
|
||||
<Footer date={new Date()} />
|
||||
</div>
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
const rootElement = document.getElementById('root')
|
||||
ReactDOM.render(<App />, rootElement)
|
||||
File diff suppressed because it is too large
Load Diff
|
After Width: | Height: | Size: 1.4 MiB |
|
After Width: | Height: | Size: 1.3 MiB |
Loading…
Reference in new issue