feat: use growthbook to determine next and previous challenges (#57435)

client/utils/gatsby/challenge-page-creator.js

@@ -72,21 +72,19 @@ function getIsFirstStepInBlock(id, edges) {
   return previous.node.challenge.block !== current.node.challenge.block;
 }
 
-function getNextChallengePath(id, edges) {
-  const next = edges[id + 1];
-  return next ? next.node.challenge.fields.slug : null;
-}
-
-function getPrevChallengePath(id, edges) {
-  const prev = edges[id - 1];
-  return prev ? prev.node.challenge.fields.slug : null;
-}
-
 function getTemplateComponent(challengeType) {
   return views[viewTypes[challengeType]];
 }
 
-exports.createChallengePages = function (createPage) {
+exports.createChallengePages = function (
+  createPage,
+  {
+    idToNextPathCurrentCurriculum,
+    idToPrevPathCurrentCurriculum,
+    idToNextPathNextCurriculum,
+    idToPrevPathNextCurriculum
+  }
+) {
   return function ({ node }, index, allChallengeEdges) {
     const {
       dashedName,
@@ -121,10 +119,14 @@ exports.createChallengePages = function (createPage) {
           template,
           required,
           isLastChallengeInBlock: isLastChallengeInBlock,
-          nextChallengePath: getNextChallengePath(index, allChallengeEdges),
-          prevChallengePath: getPrevChallengePath(index, allChallengeEdges),
+          nextChallengePath: idToNextPathCurrentCurriculum[node.id],
+          prevChallengePath: idToPrevPathCurrentCurriculum[node.id],
           id
         },
+        nextCurriculumPaths: {
+          nextChallengePath: idToNextPathNextCurriculum[node.id],
+          prevChallengePath: idToPrevPathNextCurriculum[node.id]
+        },
         projectPreview: getProjectPreviewConfig(
           node.challenge,
           allChallengeEdges

client/utils/gatsby/page-loading.ts

@@ -3,7 +3,7 @@
  * but the link of the page isn't rendered on the screen.
  * For more details, see https://github.com/freeCodeCamp/freeCodeCamp/pull/55472.
  */
-export const preloadPage = (path: string | null) => {
+export const preloadPage = (path?: string) => {
   if (!window.___loader || !path) return;
 
   window.___loader.hovering(path);