Currently, I am doing something similar.

The application is not a full React App, I am using React for dynamic Stuff, like CommentBox, which is autark. And can be included at any Point with special params..

However, all my sub Apps are loaded and included into a single file all.js, so it can be cached by the browser across pages.

When I need to include an App into the SSR Templates, I just have to include a DIV with the class __react-root and a special ID, ( the name of the React App to be rendered )

The logic is really simple:

import CommentBox from './apps/CommentBox';

import OtherApp from './apps/OtherApp';



const APPS = {

  CommentBox,

  OtherApp

};



function renderAppInElement(el) {

  var App = APPS[el.id];

  if (!App) return;



  // get props from elements data attribute, like the post_id

  const props = Object.assign({}, el.dataset);



  ReactDOM.render(<App {...props} />, el);

}



document

  .querySelectorAll('.__react-root')

  .forEach(renderAppInElement)

<div>Some Article</div>

<div id=CommentBox data-post_id=10 class=__react-root></div>



<script src=/all.js></script>

Edit

Since webpack perfectly supports code-splitting & LazyLoading, I thought it make sense to include an example where you don't need to load all your apps in one bundle, but split them up and load on demand.

import React from 'react';

import ReactDOM from 'react-dom';



const apps = {

  'One': () => import('./One'),

  'Two': () => import('./Two'),

}



const renderAppInElement = (el) => {

  if (apps[el.id])  {

    apps[el.id]().then((App) => {

      ReactDOM.render(<App {...el.dataset} />, el);

    });

  }

}