From eac361a0d498286468a97f318a8aac14abd8fc6f Mon Sep 17 00:00:00 2001
From: Thana Tingprasom <kookza01@gmail.com>
Date: Sat, 20 Jan 2024 13:05:47 +0700
Subject: [PATCH] Add Pagination

---
 content/posts/setup-uptime-kuma.md |   8 +-
 content/posts/simple-paginate.md   | 123 +++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+), 4 deletions(-)
 create mode 100644 content/posts/simple-paginate.md

diff --git a/content/posts/setup-uptime-kuma.md b/content/posts/setup-uptime-kuma.md
index 6ada084..1276b17 100644
--- a/content/posts/setup-uptime-kuma.md
+++ b/content/posts/setup-uptime-kuma.md
@@ -11,7 +11,7 @@ date = 2024-01-19T22:26:45+07:00
 
 #### 1. Basic setup
 
-```sh
+```shell
 sudo apt update && sudo apt upgrade -y
 sudo timedatectl set-timezone Asia/Bangkok
 
@@ -20,7 +20,7 @@ sudo apt install curl git -y
 
 #### 2. Install nodejs (v.20) and pm2
 
-```sh
+```shell
 curl -sL https://deb.nodesource.com/setup_20.x -o /tmp/nodesource_setup.sh
 
 sudo bash /tmp/nodesource_setup.sh
@@ -39,7 +39,7 @@ pm2 --version
 
 #### 3. Install Uptime Kuma
 
-```sh
+```shell
 git clone https://github.com/louislam/uptime-kuma.git
 
 cd uptime-kuma
@@ -57,7 +57,7 @@ pm2 save && pm2 startup
 
 #### 4. Update Uptime Kuma
 
-```sh
+```shell
 git fetch --all
 git checkout 1.23.11 --force
 
diff --git a/content/posts/simple-paginate.md b/content/posts/simple-paginate.md
new file mode 100644
index 0000000..cac61a5
--- /dev/null
+++ b/content/posts/simple-paginate.md
@@ -0,0 +1,123 @@
++++
+title = 'Simple Paginate'
+date = 2024-01-20T12:56:17+07:00
++++
+
+-   ปล. เป็น Code แบบ Simple
+-   ปล2. Code ตัวอย่างคือการใช้งานใน Express + Typescript + Mongoose
+
+ใน output ที่ตอบกลับจะเป็น
+
+```json
+{
+    "data": [],
+    "currentPage": "หน้าปัจจุบัน",
+    "nextPage": "หน้าถัดไปถ้ามี แต่ถ้าไม่มีจะเป็น Null",
+    "prevPage": "หน้าก่อนหน้าถ้ามี แต่ถ้าไม่มีจะเป็น Null",
+    "count": "จำนวน data ทั้งหมดที่มี"
+}
+```
+
+ซึ่งจะทำให้ Frontend สามารถนำไปใช้งานได้ง่ายยิ่งขึ้น
+
+#### 1. สร้างไฟล์ utils/pagination.util/ts
+
+```js
+interface PaginationParams {
+    perPage: number;
+    page: number;
+    skip: number;
+}
+
+interface PaginationResponse<T> {
+    data: T[];
+    currentPage: number;
+    nextPage?: number;
+    prevPage?: number;
+    count: number;
+}
+
+export function buildPaginationParam(
+    page: string,
+    perPage: string,
+    limit: number
+): PaginationParams {
+    // Pagination
+    const pageInt = !Number.isNaN(parseInt(page)) ? parseInt(page) : 1;
+    let perPageInt = !Number.isNaN(parseInt(perPage)) ? parseInt(perPage) : 10;
+
+    // Set a maximum limit
+    perPageInt = Math.min(perPageInt, limit);
+
+    const skip = (pageInt - 1) * perPageInt;
+
+    return {
+        perPage: perPageInt,
+        page: pageInt,
+        skip,
+    };
+}
+
+export function buildResponsePagination<T>(
+    data: T[],
+    page: number,
+    perPage: number,
+    totalCount: number
+): PaginationResponse<T> {
+    const currentPage = page;
+    const totalPages = Math.ceil(totalCount / perPage);
+
+    const hasNextPage = currentPage < totalPages;
+    const hasPrevPage = currentPage > 1;
+
+    const nextPage = hasNextPage ? currentPage + 1 : undefined;
+    const prevPage = hasPrevPage ? currentPage - 1 : undefined;
+
+    return {
+        data,
+        currentPage,
+        nextPage,
+        prevPage,
+        count: totalCount,
+    };
+}
+```
+
+#### 2. Usage
+
+```js
+const { page, perPage } = req.query
+
+const {
+    perPage: perPageInt,
+    page: pageInt,
+    skip,
+} = buildPaginationParam(page as string, perPage as string, 10)
+
+// Find all post
+const [posts, count] = await Promise.all([
+    await Post.find({})
+        .skip(skip)
+        .limit(perPageInt)
+        .lean(),
+    await Post.countDocuments(),
+])
+
+const output = buildResponsePagination(
+    posts,
+    pageInt,
+    perPageInt,
+    count
+)
+
+res.send({
+    message: SuccessMessages.GetSuccess,
+    data: output.data,
+    currentPage: output.currentPage,
+    nextPage: output.nextPage || null,
+    prevPage: output.prevPage || null,
+    count: count,
+})
+```
+
+-   ที่ต้องกำหนด Limit ไว้ด้วย เนื่องจากป้องกันการ Dump ข้อมูลจาก database และลดการทำงานของ Server ได้