previous state react code example
Example 1: setstate react js
constructor(props) {
super(props);
this.state = {
isActive: true,
};
}
checkStatus = () => {
this.setState({
'isActive' : !this.state.isActive,
});
}
Example 2: when to use previous state in useState
import React, { useState } from "react";
import ReactDOM from "react-dom";
function Counter() {
const [count, setCount] = useState(0);
return (
<div>
<h1>{count}</h1>
<button onClick={() => setTimeout(() => setCount(count + 1), 2000)}>
Delayed Counter (basic)
</button>
<button onClick={() => setTimeout(() => setCount(x => x + 1), 2000)}>
Delayed Counter (functional)
</button>
<button onClick={() => setCount(count + 1)}>Immediate Counter</button>
</div>
);
}
const rootElement = document.getElementById("root");
ReactDOM.render(<Counter />, rootElement);
Example 3: react lifecycle hooks
class Content extends React.Component {
componentWillMount() {
this.setState({ activities: data });
}
}