ClientOnly.jsx

client-only.jsx

/* eslint-disable react/prop-types, react/no-did-mount-set-state */
import React from 'react';

let initialRender = true;

export default class ClientOnly extends React.Component {
  constructor(props) {
    super(props);
    this.state = {initialRender};
  }

  componentDidMount() {
    if (this.state.initialRender) {
      initialRender = false;
      this.setState({initialRender});
    }
  }

  render() {
    return !this.state.initialRender ? this.props.children : <div />;
  }
}
ClientOnly.propTypes = {
  children: React.PropTypes.element
};

ex.jsx

        <ClientOnly>
          <div style={{flex: 1}}>
            <a
                href="#"
                className={`btn btn-transparent pull-right ${css.loginButton}`}
                {... onActivate(() => this.props.onSignIn())}
            >
              Log In or Register
            </a>
          </div>
        </ClientOnly>