Converting Message-Board Project to React

Here is my App.js:

<input
                className="input"
                placeholder="/b/general/"
                type="text"
                value={this.state.get}
                onChange={e => this.setState({ get: e.target.value })}
                />

Here is my server.js route:

app.route('/b/:board/')
  .get(function (req, res) {
    res.sendFile(process.cwd() + '/client/public/board.html');
  });

How can I get the input from the user to REDIRECT to the board.html if they are running on different ports? It sounds like you can redirect with react-router, but that only seems to work on the same port.