28. async_await.md

async / await

What?

Asynchronous Requests in a Synchronous Way**

기존에는 then() , catch() 를 이용해서 비동기 처리를 했습니다.

프로젝트에 적용해보기

feed.js에 적용하기

1. getposts

   • 기존 코드

     exports.getPosts = (req, res, next) => {
       const currentPage = req.query.page || 1;
       const perPage = 2;
       let totalItems;
       // 총 item 갯수 세기
       Post.find()
         .countDocuments()
         .then(count => {
           totalItems = count;
           return Post.find()
             .skip((currentPage - 1) * perPage)
             .limit(perPage);
         })
         .then(posts => {
           res.status(200).json({
             message: 'Fetched posts successfully.',
             posts: posts,
             totalItems: totalItems
           });
         })
         .catch(err => {
           if (!err.statusCode) {
             err.statusCode = 500;
           }
         });
     };

   • async / await 적용

     exports.getPosts = async (req, res, next) => {
       const currentPage = req.query.page || 1;
       const perPage = 2;
     
       try {
         // 총 item 갯수 세기
         const totalItems = await Post.find().countDocuments();
         const posts = await Post.find()
           .skip((currentPage - 1) * perPage)
           .limit(perPage);
     
         res.status(200).json({
           message: 'Fetched posts successfully.',
           posts: posts,
           totalItems: totalItems
         });
       } catch (err) {
         if (!err.statusCode) {
           err.statusCode = 500;
         }
         next(err);
       }
     };