Question

我有两个查询，一个用于检查用户当前是否关注帖子作者，另一个用于检查用户是否已经喜欢该帖子。

我正在使用类似：if（（likes）＆amp;＆amp;（resault）来渲染具有正确对象的页面，但它似乎不起作用。

我花了一些时间试图解决这个问题，所以我发布了一个很长的代码，请耐心等待：

if (req.user) { // if the user is currently logged in
  var q = 'SELECT * FROM follows WHERE followee_id =\'' + author_id + '\' AND follower_id =\'' + req.user.id + '\'';
  connection.query(q, function (err, resault) {
    if (err) {
      console.log(err);
    }
    var isfollowing = {
      follower_id: resault[0].follower_id,
      followee_id: resault[0].followee_id
    };

    var q = 'SELECT * FROM likes WHERE user_id =\'' + req.user.id + '\' AND post_id =\'' + post_id + '\'';
    connection.query(q, function (err, likes) {
      if (err) {
        console.log(err);
      }
      var hasLikes = {
        user_id: likes[0].user_id,
        post_id: likes[0].post_id
      };

      if ((likes.length > 0) && (resault.length > 0)) { // if the user has likes and is following users
        console.log('has likes, has follows');
        res.render('single', {
          showPost: post,
          comments: comments,
          numComments: numComments,
          hasLikes: hasLikes,
          likes: likes,
          isfollowing: isfollowing,
          resault: resault
        });

      } else if ((likes.length < 0) && (resault.length > 0)) {
        res.render('single', {
          showPost: post,
          comments: comments,
          numComments: numComments,
          isfollowing: isfollowing,
          resault: resault,
          likes: likes
        });
        console.log('NO likes, has follows');

      } else if ((likes.length > 0) && (resault.length < 0)) {
        console.log('has likes, NO follows');
        res.render('single', {
          showPost: post,
          comments: comments,
          numComments: numComments,
          hasLikes: hasLikes,
          resault: resault,
          likes: likes
        });

      } else {
        console.log('has nothing');
        res.render('single', {
          showPost: post,
          comments: comments,
          numComments: numComments,
          resault: resault,
          likes: likes
        });

      }
      console.log(isfollowing);
      console.log(hasLikes);
    });

  });
}

完整路线/代码：

 app.get("/single/:id", function(req, res){
    var post_id = req.params.id;
    var q = "SELECT *, DATE_FORMAT(posts.created_at, '%m/%d/%Y') AS created_at FROM posts INNER JOIN users ON posts.user_id=users.id WHERE posts.id =" + post_id;
    connection.query(q, function(err, results){
        if (err) throw err;
        //render post
        var post_title = results[0].post_title;
        var image = results[0].image;
        var post_description = results[0].post_description;
        var username=results[0].username;
        var bio = results[0].bio;
        var requests = results[0].requests;
        var author_id = results[0].user_id;
        //store all in one variable
        var post = {post_title:post_title, image:image, post_description:post_description,post_id:post_id,username:username, bio:bio, avatar:results[0].avatar, requests:requests, author_id:author_id, post_date:results[0].created_at};
        var q = "SELECT *,  DATE_FORMAT(comments.created_at, '%m/%d/%Y') AS created_at FROM comments INNER JOIN users ON comments.user_id=users.id WHERE post_id =" + post_id;
        connection.query(q, function(err, comments){
                 if (err) throw err;
                 var numComments = comments.length;

                 if(req.user){ // if the user is currently logged in
                     var q ="SELECT * FROM follows WHERE followee_id ='" + author_id + "' AND follower_id ='" + req.user.id +"'";
                     connection.query(q, function(err, resault){
                        if(err){
                            console.log(err);
                        }
                     var isfollowing = {follower_id:resault[0].follower_id, followee_id:resault[0].followee_id};

                     var q ="SELECT * FROM likes WHERE user_id ='" + req.user.id + "' AND post_id ='" + post_id +"'";
                     connection.query(q, function(err, likes){
                        if(err){
                            console.log(err);
                        }
                        var hasLikes = {user_id:likes[0].user_id, post_id:likes[0].post_id};

                        if ((likes.length > 0) && (resault.length > 0)) { // if the user has likes and is following users
                          console.log("has likes, has follows")
                           res.render("single",{showPost:post, comments:comments, numComments:numComments, hasLikes:hasLikes, likes:likes, isfollowing:isfollowing, resault:resault});

                        } else if((likes.length < 0)  && (resault.length > 0)){
                        res.render("single",{showPost:post, comments:comments, numComments:numComments, isfollowing:isfollowing, resault:resault, likes:likes});
                        console.log("NO likes, has follows")

                        } else if ((likes.length > 0) && (resault.length < 0) ){
                            console.log("has likes, NO follows")
                            res.render("single",{showPost:post, comments:comments, numComments:numComments, hasLikes:hasLikes, resault:resault, likes:likes});

                        } else {
                            console.log("has nothing")
                            res.render("single",{showPost:post, comments:comments, numComments:numComments, resault:resault, likes:likes});

                        }
                        console.log(isfollowing);
                        console.log(hasLikes);
                     });

                     });

                 } else { // if user not logged in
                     res.render("single",{showPost:post, comments:comments, numComments:numComments});
                 }

我开始认为这不是最好的方法吗？有小费吗？谢谢

Answer 1

发现我的错误。

我使用的是：

likes.length < 0

检查数组是否为空，我应该使用它：

!likes.length

node js如何检查两个MySQL查询是否已返回数据和呈现页面

1 个答案: