javascript - 如何在 sequelize findAll 方法中使用 left Join

Question

我如何能够使用 sequelize findAll 来检查当前用户是否喜欢每个帖子。
where 查询过滤了 posts 数组对象。它需要检查当前用户是否喜欢某个帖子，但仍会获取所有数据。

我需要做左连接吗？ where userId === req.session.user.id
Get all posts and check if user liked each post

我正在使用 sequelize 和 postgres。它几乎只是 sql 。

我应该如何使用 sequelize 实现这一目标

帖子结构是什么样的



以这段代码为例，这是我制作的laravel应用程序，我想在sequelize中实现相同的实现

php(示例)

public function getPosts( )
    {
        $posts = Post::with('user')
                     ->with(['likes' => function ($query) {
                                $query->whereNull('deleted_at');
                                $query->where('user_id', auth()->user()->id);
                            }])
                      ->with(['comments' => function($query) {

                            $query->with('user');
                        }])->orderBy('created_at', 'desc')
                        ->get();
        $data = $posts->map(function(Post $post)
        { 
            $user = auth()->user();
            if($user->can('delete', $post)) {
                $post['deletable'] = true;
            }
            if($user->can('update', $post)) {
                $post['update'] = true;
            }
            // $comment = new Comment();
            $post['likedByMe'] = $post->likes->count() == 0 ? false : true;
            $post['likesCount'] = Like::where('post_id', $post->id)->get()->count();
            $post['createdAt'] = $post->created_at->diffForHumans();
            $post['createdAt'] = $post->updated_at->diffForHumans();

            return $post;


        });
        return response()->json($data); 
    }

post.controller.js

 getPosts: async (req: any, res: Response) => {
    // use async/await here
    const posts = await models.Post.findAll({
      include: [
        { model: models.User, as: "author", attributes: ["username"] },
        // limit the likes based on the logged in user
        {
          model: models.Likes
        }
      ],
      order: [["createdAt", "DESC"]],
      limit: 6
    });
    // i dont think this is the right approach. 
    posts.forEach(post => {
      post.Likes.forEach(like => {
        console.log(like.userId);
        if (like.userId === req.session.user.id) {
          post.setDataValue("likedByMe", true);
        } else {
          post.setDataValue("likedByMe", false);
        }
      });
    });

    return res.json(posts);

post.js

"use strict";
module.exports = (sequelize, DataTypes) => {
    var Post = sequelize.define("Post", {
        title: DataTypes.STRING,
        postContent: DataTypes.STRING,
        liked: {
            type: DataTypes.VIRTUAL,
            allowNull: false,
            defaultValue: false,
            get: function () {
                return this.getDataValue('Likes').length ? true : false;
            }
        },
        likeCounts: {
            type: DataTypes.INTEGER,
            allowNull: false,
            defaultValue: 0,
            validate: {
                min: 0,
            }
        },
        authorId: DataTypes.INTEGER
    }, {});
    Post.associate = function (models) {
        Post.belongsTo(models.User, {
            as: "author",
            foreignKey: "authorId",
            onDelete: "CASCADE"
        });
        Post.hasMany(models.Likes, {
            foreignKey: "resourceId",
            timestamps: false,
            targetKey: "id",
            onDelete: "CASCADE"
        });
    };
    return Post;
};

Answer 1

我认为这个 forEach 语句有助于确定当前用户是否喜欢该帖子。

 getPosts: async (req: any, res: Response) => {
    // use async/await here
    const posts = await models.Post.findAll({
      include: [
        { model: models.User, as: "author", attributes: ["username"] },
        // limit the likes based on the logged in user
        {
          model: models.Likes
        }
      ],
      order: [["createdAt", "DESC"]],
      limit: 6
    });

    posts.forEach(post => {
      if (post.Likes.length === 0) {
        post.setDataValue("likedByMe", false);
      }
      post.Likes.forEach(like => {
        console.log(like.userId);
        if (like.userId === req.session.user.id) {
          post.setDataValue("likedByMe", true);
        } else {
          post.setDataValue("likedByMe", false);
        }
      });
    });

    return res.json(posts);
  },