gatsby-ssr.js

import React from 'react';
import { renderToString } from 'react-dom/server';
import { MockedProvider } from 'react-apollo/test-utils';

export const replaceRenderer = ({ bodyComponent, replaceBodyHTMLString }) => {
    const ConnectedBody = () => (
        <MockedProvider>
            {bodyComponent}
        </MockedProvider>
    );
    const result = renderToString(<ConnectedBody />);
    
    replaceBodyHTMLString(result);
};