Refactor most getServerProps to fetch independent request in parallel and projected the data only to return the necessary fields and changed some functions

src/pages/official-exam.tsx

@@ -4,7 +4,7 @@ import Button from "@/components/Low/Button";
 import Separator from "@/components/Low/Separator";
 import ProfileSummary from "@/components/ProfileSummary";
 import { Session } from "@/hooks/useSessions";
-import { Grading } from "@/interfaces";
+import { Grading, Module } from "@/interfaces";
 import { EntityWithRoles } from "@/interfaces/entity";
 import { Exam } from "@/interfaces/exam";
 import { InviteWithEntity } from "@/interfaces/invite";
@@ -12,14 +12,13 @@ import { Assignment } from "@/interfaces/results";
 import { Stat, User } from "@/interfaces/user";
 import { sessionOptions } from "@/lib/session";
 import useExamStore from "@/stores/exam";
-import { filterBy, findBy, mapBy, redirect, serialize } from "@/utils";
+import { findBy, mapBy, redirect, serialize } from "@/utils";
 import { requestUser } from "@/utils/api";
 import {
   activeAssignmentFilter,
   futureAssignmentFilter,
 } from "@/utils/assignments";
 import { getAssignmentsByAssignee } from "@/utils/assignments.be";
-import { getEntitiesWithRoles } from "@/utils/entities.be";
 import { getExamsByIds } from "@/utils/exams.be";
 import { sortByModule } from "@/utils/moduleUtils";
 import { checkAccess } from "@/utils/permissions";
@@ -53,32 +52,59 @@ export const getServerSideProps = withIronSessionSsr(async ({ req, res }) => {
 
   if (!checkAccess(user, ["admin", "developer", "student"]))
     return redirect("/");
+  const assignments = (await getAssignmentsByAssignee(
+    user.id,
+    {
+      archived: { $ne: true },
+    },
+    {
+      _id: 0,
+      id: 1,
+      name: 1,
+      startDate: 1,
+      endDate: 1,
+      exams: 1,
+      results: 1,
+    },
+    {
+      sort: { startDate: 1 },
+    }
+  )) as Assignment[];
 
-  const entityIDS = mapBy(user.entities, "id") || [];
-
-  const entities = await getEntitiesWithRoles(entityIDS);
-  const assignments = await getAssignmentsByAssignee(user.id, {
-    archived: { $ne: true },
-  });
-  const sessions = await getSessionsByUser(user.id, 0, {
-    "assignment.id": { $in: mapBy(assignments, "id") },
-  });
+  const sessions = await getSessionsByUser(
+    user.id,
+    0,
+    {
+      "assignment.id": { $in: mapBy(assignments, "id") },
+    },
+    {
+      _id: 0,
+      id: 1,
+      assignment: 1,
+    }
+  );
 
   const examIDs = uniqBy(
-    assignments.flatMap((a) =>
-      filterBy(a.exams, "assignee", user.id).map(
-        (e: any) => ({
-          module: e.module,
-          id: e.id,
-          key: `${e.module}_${e.id}`,
-        })
-      )
+    assignments.reduce<{ module: Module; id: string; key: string }[]>(
+      (acc, a) => {
+        a.exams.forEach((e) => {
+          if (e.assignee === user.id)
+            acc.push({
+              module: e.module,
+              id: e.id,
+              key: `${e.module}_${e.id}`,
+            });
+        });
+        return acc;
+      },
+      []
     ),
     "key"
   );
+
   const exams = await getExamsByIds(examIDs);
 
-  return { props: serialize({ user, entities, assignments, exams, sessions }) };
+  return { props: serialize({ user, assignments, exams, sessions }) };
 }, sessionOptions);
 
 const destination = Buffer.from("/official-exam").toString("base64");
@@ -109,11 +135,12 @@ export default function OfficialExam({
     });
 
     if (assignmentExams.every((x) => !!x)) {
+      const sortedAssignmentExams = assignmentExams.sort(sortByModule);
       dispatch({
         type: "INIT_EXAM",
         payload: {
-          exams: assignmentExams.sort(sortByModule),
-          modules: mapBy(assignmentExams.sort(sortByModule), "module"),
+          exams: sortedAssignmentExams,
+          modules: mapBy(sortedAssignmentExams, "module"),
           assignment,
         },
       });
@@ -144,12 +171,16 @@ export default function OfficialExam({
     [assignments]
   );
 
-  const assignmentSessions = useMemo(
-    () =>
-      sessions.filter((s) =>
-        mapBy(studentAssignments, "id").includes(s.assignment?.id || "")
-      ),
-    [sessions, studentAssignments]
+  const assignmentSessions = useMemo(() => {
+    const studentAssignmentsIDs = mapBy(studentAssignments, "id");
+    return sessions.filter((s) =>
+      studentAssignmentsIDs.includes(s.assignment?.id || "")
+    );
+  }, [sessions, studentAssignments]);
+
+  const entityLabels = useMemo(
+    () => mapBy(entities, "label")?.join(","),
+    [entities]
   );
 
   return (
@@ -167,7 +198,7 @@ export default function OfficialExam({
       <>
         {entities.length > 0 && (
           <div className="absolute right-4 top-4 rounded-lg bg-neutral-200 px-2 py-1">
-            <b>{mapBy(entities, "label")?.join(", ")}</b>
+            <b>{entityLabels}</b>
           </div>
         )}
 
@@ -191,20 +222,18 @@ export default function OfficialExam({
           <span className="text-mti-gray-taupe scrollbar-hide flex gap-8 overflow-x-scroll">
             {studentAssignments.length === 0 &&
               "Assignments will appear here. It seems that for now there are no assignments for you."}
-            {studentAssignments
-              .sort((a, b) => moment(a.startDate).diff(b.startDate))
-              .map((a) => (
-                <AssignmentCard
-                  key={a.id}
-                  assignment={a}
-                  user={user}
-                  session={assignmentSessions.find(
-                    (s) => s.assignment?.id === a.id
-                  )}
-                  startAssignment={startAssignment}
-                  resumeAssignment={loadSession}
-                />
-              ))}
+            {studentAssignments.map((a) => (
+              <AssignmentCard
+                key={a.id}
+                assignment={a}
+                user={user}
+                session={assignmentSessions.find(
+                  (s) => s.assignment?.id === a.id
+                )}
+                startAssignment={startAssignment}
+                resumeAssignment={loadSession}
+              />
+            ))}
           </span>
         </section>