serverRender.js

import React from "react";
import ReactDOMServer from "react-dom/server";
import App from "./src/components/App";
import config from "./config";
import axios from "axios";

const getApiUrl = contestId => {
    if (contestId) {
        return `${config.serverUrl}/api/contests/${contestId}`;
    }
    return `${config.serverUrl}/api/contests`;
};

const getInitialData = (contestId, apiData) => {
    if (contestId) {
        return {
            currentContestId: apiData.id,
            contests: {
                [apiData.id]: apiData
            }
        }
    }
    return {
        contests: apiData.contests
    }
};

const serverRender = (contestId) =>
    axios.get(getApiUrl(contestId))
        .then(resp => {
            const initialData = getInitialData(contestId, resp.data);
            return { 
                initialMarkup: ReactDOMServer.renderToString(
                    <App initialData={initialData}/>
                ),
                initialData 
            }    
        });

export default serverRender;