How to write async await

async-await.txt

async function addInterestedCategories(uid, categories) {
    await User.findOneAndUpdate({ uid: uid },
        { $addToSet: { interested_categories: categories } }, { new: true}).exec()
}

exports.getPost = async (req, res, next) => {
    const postUpdate = await Post.findOneAndUpdate({ postID: req.params.postid
                                            , viewedBy: { $not: { $elemMatch: { uid: req.query.uid } } }
                                        },
                                            { $addToSet: { viewedBy: USER }, $inc: { totalViews: 1} }, { new: true })
                                        .exec()

    const countUpdate = await addViewCount(req.query.uid, posts[0].uid, req.params.postid)
    const categoryupdate = await addInterestedCategories(req.query.uid, posts[0].categories)
    
    // response will be sent when all promises are resolved
    Promise.all([countUpdate, categoryupdate, postUpdate]).then(() => {
        console.log("request complete")
        res.status(200).json(commonController.moderatePost(posts[0]));
    })
    // if you want to execute the task asynchronously
    await addInterestedCategories(req.query.uid, posts[0].categories)
}