Update gatsby-browser.js

Author: Rob3rtH

examples/using-page-transitions/gatsby-browser.js

@@ -10,7 +10,8 @@ const timeout = 250
 const historyExitingEventType = `history::exiting`
 
 const getUserConfirmation = (pathname, callback) => {
-  const event = new CustomEvent(historyExitingEventType, { detail: { pathname } })
+  const event = document.createEvent("CustomEvent");
+  event.initCustomEvent(historyExitingEventType, false, false, { detail: { pathname } });
   window.dispatchEvent(event)
   setTimeout(() => {
     callback(true)
@@ -85,4 +86,4 @@ exports.replaceComponentRenderer = ({ props, loader }) => {
     return undefined
   }
   return createElement(ReplaceComponentRenderer, { ...props, loader })
-}
+}