Implemented backend pagination for feed posts

web/__tests__/pages/api/post/post.int.test.ts

@@ -278,5 +278,48 @@ describe("[API] Post - Integration Test", () => {
       expect(uncoveredPosts.length).toBe(expectedUncoveredPosts.length);
       expect(uncoveredPosts).toMatchObject(expectedUncoveredPosts);
     });
+
+    test("pagination", async () => {
+      const response = await Post.insertMany(randomFeedPosts);
+      expect(response).not.toBeNull();
+
+      const serializedFeedPosts = randomFeedPosts.map((post) => ({
+        ...post,
+        _id: post._id.toString(),
+      }));
+
+      const postFilters = {
+        type: Object.values(FosterType),
+        breed: Object.values(Breed),
+        age: Object.values(Age),
+        size: Object.values(Size),
+        gender: Object.values(Gender),
+        behavioral: Object.values(Behavioral),
+        goodWith: [],
+      };
+
+      const allPosts = await caller.post.getFilteredPosts({
+        postFilters,
+      });
+      expect(allPosts).not.toBeNull();
+      expect(allPosts.length).toBe(randomFeedPosts.length);
+
+      let resultsPerPage = 4;
+      let page = 2;
+      const paginatedPosts = (
+        await caller.post.getFilteredPosts({
+          postFilters,
+          resultsPerPage: resultsPerPage,
+          page: page,
+        })
+      ).map((post) => ({ ...post, _id: post._id.toString() }));
+      const expectedPaginatedPosts = serializedFeedPosts
+        .sort((a, b) => b.date.getTime() - a.date.getTime())
+        .slice(resultsPerPage * (page - 1), resultsPerPage * page);
+
+      expect(paginatedPosts).not.toBeNull();
+      expect(paginatedPosts.length).toBe(expectedPaginatedPosts.length);
+      expect(paginatedPosts).toMatchObject(expectedPaginatedPosts);
+    });
   });
 });

web/db/actions/Post.ts

@@ -1,4 +1,4 @@
-import { ClientSession, FilterQuery, Types, UpdateQuery } from "mongoose";
+import { ClientSession, FilterQuery, Types } from "mongoose";
 import Post from "../models/Post";
 import {
   IFeedPost,
@@ -343,7 +343,12 @@ async function getAttachments(oid: Types.ObjectId) {
   return attachInfo;
 }
 
-async function getFilteredPosts(filter: FilterQuery<IPost>, userUid: string) {
+async function getFilteredPosts(
+  filter: FilterQuery<IPost>,
+  userUid: string,
+  resultsPerPage?: number,
+  page?: number
+) {
   const posts = await Post.aggregate([
     {
       $match: filter,
@@ -372,6 +377,8 @@ async function getFilteredPosts(filter: FilterQuery<IPost>, userUid: string) {
     },
   ])
     .sort({ date: -1 })
+    .skip((resultsPerPage ?? 1000) * ((page ?? 1) - 1))
+    .limit(resultsPerPage ?? 1000)
     .exec();
   return posts;
 }

web/server/routers/post.ts

@@ -1,5 +1,5 @@
 import { TRPCError } from "@trpc/server";
-import { z, ZodArray } from "zod";
+import { z } from "zod";
 import {
   createPost,
   deletePost,
@@ -27,7 +27,7 @@ import {
   Trained,
   IPost,
 } from "../../utils/types/post";
-import { findUserByEmail, updateUserByUid } from "../../db/actions/User";
+import { findUserByEmail } from "../../db/actions/User";
 import { router, procedure } from "../trpc";
 import nodemailer from "nodemailer";
 import { FilterQuery, Types } from "mongoose";
@@ -367,6 +367,8 @@ export const postRouter = router({
       z.object({
         postFilters: postFilterSchema,
         covered: z.optional(z.boolean()),
+        resultsPerPage: z.optional(z.number()),
+        page: z.optional(z.number()),
       })
     )
     .query(async ({ input, ctx }) => {
@@ -426,7 +428,9 @@ export const postRouter = router({
       try {
         const filteredPosts = await getFilteredPosts(
           baseFilter,
-          ctx.session.uid
+          ctx.session.uid,
+          input.resultsPerPage,
+          input.page
         );
         return filteredPosts;
       } catch (e) {