usestate hook

1import React, { useState } from 'react';
2
3function Example() {
4  // Declare a new state variable, which we'll call "count"  
5  const [count, setCount] = useState(0);
6  return (
7    <div>
8      <p>You clicked {count} times</p>
9      <button onClick={() => setCount(count + 1)}>
10        Click me
11      </button>
12    </div>
13  );
14}

1class Example extends React.Component {
2  constructor(props) {
3    super(props);
4    this.state = {
5      count: 0
6    };
7  }
8
9  render() {
10    return (
11      <div>
12        <p>You clicked {this.state.count} times</p>
13        <button onClick={() => this.setState({ count: this.state.count + 1 })}>
14          Click me
15        </button>
16      </div>
17    );
18  }
19}

1import React, { useEffect } from 'react';
2
3export const App: React.FC = () => {
4  
5  useEffect(() => {
6        
7  }, [/*Here can enter some value to call again the content inside useEffect*/])
8  
9  return (
10    <div>Use Effect!</div>
11  );
12}

1function Counter({initialCount}) {
2  const [count, setCount] = useState(initialCount);
3  return (
4    <>
5      Count: {count}
6      <button onClick={() => setCount(initialCount)}>Reset</button>
7      <button onClick={() => setCount(prevCount => prevCount - 1)}>-</button>
8      <button onClick={() => setCount(prevCount => prevCount + 1)}>+</button>
9    </>
10  );
11}

1import React, { useState } from 'react';
2
3function Example() {
4	
5  const [count, setCount] = useState(0);
6  
7  return (
8    <div>
9      <p>You clicked {count} times</p>
10      <button onClick={() => setCount(count + 1)}>
11        Click me
12      </button>
13    </div>
14  );
15}

1 1:  import React, { useState } from 'react'; 2:
2 3:  function Example() {
3 4:    const [count, setCount] = useState(0); 5:
4 6:    return (
5 7:      <div>
6 8:        <p>You clicked {count} times</p>
7 9:        <button onClick={() => setCount(count + 1)}>10:         Click me
811:        </button>
912:      </div>
1013:    );
1114:  }