link to onclick react

import React from 'react';

const App = () => {
  
const message = () => {
 console.log("Hello World!") 
}

return (
<button onClick={message}> Press me to print a message! </button>
  );
}

var Box = React.createClass({
  getInitialState: function() {
    return {windowWidth: window.innerWidth};
  },

  handleResize: function(e) {
    this.setState({windowWidth: window.innerWidth});
  },

  componentDidMount: function() {
    window.addEventListener('resize', this.handleResize);
  },

  componentWillUnmount: function() {
    window.removeEventListener('resize', this.handleResize);
  },

  render: function() {
    return <div>Current window width: {this.state.windowWidth}</div>;
  }
});

ReactDOM.render(<Box />, mountNode);

<Link to={`/users/${user.id}`} activeClassName="active">{user.name}</Link>
// becomes one of these depending on your History and if the route is
// active
<a href="/users/123" class="active">Michael</a>
<a href="#/users/123">Michael</a>

// change the activeClassName
<Link to={`/users/${user.id}`} activeClassName="current">{user.name}</Link>

// change style when link is active
<Link to="/users" style={{color: 'white'}} activeStyle={{color: 'red'}}>Users</Link>