react preventdefault code example
Example 1: js preventdefault
function(event) {
event.preventDefault();
}
Example 2: preventdefault
e.preventDefault();
Example 3: prevent default react
import React from 'react';
const initialList = [
'Learn React',
'Learn Firebase',
'Learn GraphQL',
];
const ListWithAddItem = () => {
const [value, setValue] = React.useState('');
const [list, setList] = React.useState(initialList);
const handleChange = event => {
setValue(event.target.value);
};
const handleSubmit = event => {
if (value) {
setList(list.concat(value));
}
setValue('');
event.preventDefault();
};
return (
<div>
<ul>
{list.map(item => (
<li key={item}>{item}</li>
))}
</ul>
<form onSubmit={handleSubmit}>
<input type="text" value={value} onChange={handleChange} />
<button type="submit">Add Item</button>
</form>
</div>
);
};
export default ListWithAddItem;
Example 4: react button onclick
import React, { Component } from 'react';
class App extends Component {
constructor(props) {
super(props);
this.sayHello = this.sayHello.bind(this);
}
sayHello() {
alert('Hello!');
}
return (
<button onClick={this.sayHello}>
Click me!
</button>
);
}
export default App;