react class components state code example
Example 1: set state
class App extends React.Component {
state = { count: 0 }
handleIncrement = () => {
this.setState({ count: this.state.count + 1 })
}
handleDecrement = () => {
this.setState({ count: this.state.count - 1 })
}
render() {
return (
<div>
<div>
{this.state.count}
</div>
<button onClick={this.handleIncrement}>Increment by 1</button>
<button onClick={this.handleDecrement}>Decrement by 1</button>
</div>
)
}
}
Example 2: how to write statefull class in react
import React, {Component} from 'react'
class Pigeons extends Component {
constructor() {
super()
this.state = {
pigeons: []
}
}
render() {
return (
<div>
<p>Look at all the pigeons spotted today!</p>
<ul>
{this.state.pigeons.map(pigeonURL => {
return <li><img src={pigeonURL} /></li>
})}
</ul>
</div>
)
}
}
Example 3: set state
setState({ searchTerm: event.target.value })