Additional polyfill for Turbo

app/frontend/application.js

@@ -9,6 +9,7 @@ import "core-js/stable"
 import "regenerator-runtime/runtime"
 import "@stimulus/polyfills"
 import "custom-event-polyfill"
+import "intersection-observer"
 //
 
 require.context("govuk-frontend/govuk/assets")

package.json

@@ -25,6 +25,7 @@
     "custom-event-polyfill": "^1.0.7",
     "file-loader": "^6.2.0",
     "govuk-frontend": "^4.0.1",
+    "intersection-observer": "^0.12.0",
     "mini-css-extract-plugin": "^2.6.0",
     "regenerator-runtime": "^0.13.9",
     "sass": "^1.49.9",

yarn.lock

@@ -1863,6 +1863,11 @@ interpret@^2.2.0:
   resolved "https://registry.yarnpkg.com/interpret/-/interpret-2.2.0.tgz#1a78a0b5965c40a5416d007ad6f50ad27c417df9"
   integrity sha512-Ju0Bz/cEia55xDwUWEa8+olFpCiQoypjnQySseKtmjNrnps3P+xfpUmGr90T7yjlVJmOtybRvPXhKMbHr+fWnw==
 
+intersection-observer@^0.12.0:
+  version "0.12.0"
+  resolved "https://registry.yarnpkg.com/intersection-observer/-/intersection-observer-0.12.0.tgz#6c84628f67ce8698e5f9ccf857d97718745837aa"
+  integrity sha512-2Vkz8z46Dv401zTWudDGwO7KiGHNDkMv417T5ItcNYfmvHR/1qCTVBO9vwH8zZmQ0WkA/1ARwpysR9bsnop4NQ==
+
 is-arrayish@^0.2.1:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/is-arrayish/-/is-arrayish-0.2.1.tgz#77c99840527aa8ecb1a8ba697b80645a7a926a9d"