refactor: add Pagination class

packages/analytics/tests/pagination.test.js

@@ -0,0 +1,37 @@
+import mongoose from 'mongoose'
+import { Desc } from '../src/models/pagination.js'
+
+describe('Pagination', () => {
+  it('should return correct limit', async () => {
+    const pagination = new Desc(10)
+
+    expect(pagination.limit()).toMatchObject({ $limit: 10 })
+  })
+
+  it('should return correct order', async () => {
+    const pagination = new Desc(10)
+
+    expect(pagination.order('_id')).toMatchObject({ $sort: { _id: -1 } })
+    expect(pagination.order('time')).toMatchObject({ $sort: { time: -1 } })
+  })
+
+  it('should return correct match stage for empty nextKey', async () => {
+    const pagination = new Desc(10)
+
+    expect(pagination.matchStage('_id')).toMatchObject({ $match: {} })
+  })
+
+  it('should return correct match stage for empty nextKey', async () => {
+    const nextKeyStr = '656c7fea28a4c087bfcefe12'
+    const pagination = new Desc(10, nextKeyStr)
+    const nextKey = new mongoose.Types.ObjectId(nextKeyStr)
+
+    expect(pagination.matchStage('_id')).toMatchObject({
+      $match: {
+        _id: {
+          $lt: nextKey,
+        },
+      },
+    })
+  })
+})