Add setTimeout before calling onRouteUpdate to ensure React has written to DOM before plugins run code

packages/gatsby-plugin-google-analytics/src/gatsby-browser.js

@@ -1,10 +1,7 @@
 exports.onRouteUpdate = function({ location }) {
   // Don't track while developing.
   if (process.env.NODE_ENV === `production` && typeof ga === `function`) {
-    // Wait for the title update (see #2478)
-    setTimeout(() => {
-      window.ga(`set`, `page`, (location || {}).pathname)
-      window.ga(`send`, `pageview`)
-    }, 0)
+    window.ga(`set`, `page`, (location || {}).pathname)
+    window.ga(`send`, `pageview`)
   }
 }

packages/gatsby-plugin-twitter/src/gatsby-browser.js

@@ -1,12 +1,9 @@
 exports.onRouteUpdate = function({ location }) {
-  // Wait to ensure page is rendered first.
-  setTimeout(() => {
-    if (
-      typeof twttr !== `undefined` &&
-      window.twttr.widgets &&
-      typeof window.twttr.widgets.load === `function`
-    ) {
-      window.twttr.widgets.load()
-    }
-  }, 0)
+  if (
+    typeof twttr !== `undefined` &&
+    window.twttr.widgets &&
+    typeof window.twttr.widgets.load === `function`
+  ) {
+    window.twttr.widgets.load()
+  }
 }

packages/gatsby/cache-dir/production-app.js

@@ -110,7 +110,10 @@ apiRunnerAsync(`onClientEntry`).then(() => {
 
       history.listen((location, action) => {
         if (!maybeRedirect(location.pathname)) {
-          apiRunner(`onRouteUpdate`, { location, action })
+          // Make sure React has had a chance to flush to DOM first.
+          setTimeout(() => {
+            apiRunner(`onRouteUpdate`, { location, action })
+          }, 0)
         }
       })
     }