fix(ssr): disableSSR option

packages/core/client/index.js

@@ -10,7 +10,10 @@ import set from 'lodash/fp/set';
 import { actionLocationChange } from 'actions';
 import Cookies from 'universal-cookie';
 import App from 'components/app';
-import { getValueFromConfig } from 'config/irving/getValueFromConfig';
+import {
+  getValueFromConfig,
+  getValueFromUserConfig,
+} from 'config/irving/getValueFromConfig';
 import preloadedStateDenylist from 'config/preloadedStateDenylist';
 import rootReducer from 'reducers';
 import defaultState from 'reducers/defaultState';
@@ -66,12 +69,16 @@ history.listen((location, action) => {
   ));
 });
 
+// Determine if user wants to disable SSR.
+const disableSSR = getValueFromUserConfig('disableSSR', false);
+const renderMethod = disableSSR ? 'render' : 'hydrate';
+
 const render = () => {
   const rootEl = document.getElementById('root');
   // It is imperative that the server React component tree matches the client
   // component tree, so that the client can re-hydrate the app from the server
   // rendered markup, otherwise the app will be completely re-rendered.
-  ReactDOM.hydrate(
+  ReactDOM[renderMethod](
     <Provider store={store}>
       <App />
     </Provider>,

packages/core/server/utils/getTemplateVars.js

@@ -2,7 +2,10 @@ import React from 'react';
 import { renderToString } from 'react-dom/server';
 import omit from 'lodash/fp/omit';
 import mergeWith from 'lodash/mergeWith';
-import { getConfigValues } from 'config/irving/getValueFromConfig';
+import {
+  getConfigValues,
+  getValueFromUserConfig,
+} from 'config/irving/getValueFromConfig';
 import { getEnv, getSiteConfig } from 'config/multisite';
 
 export const defaultHead = {
@@ -19,6 +22,9 @@ export const defaultHead = {
   end: [],
 };
 
+// Determine if user wants to disable SSR.
+const disableSSR = getValueFromUserConfig('disableSSR', false);
+
 /**
  * Check if a value is a function and, if so, call that function to get underlying value.
  *
@@ -151,6 +157,6 @@ export default function getTemplateVars(
   return {
     ...mergedVars,
     head: mergedHead,
-    appHtml,
+    appHtml: disableSSR ? '' : appHtml,
   };
 }