What Structure For Create Tree Category And Set In Posts Is Better? And Find Posts By Selected Category In Mern

I'm using MERN to develop my project, I have tree category with this structure: {id: { type: Number }, parent_id: { type: Number }, name: { type: String }, sub: { t

Solution 1:

I see that you're using $all operator.

The $all operator selects the documents where the value of a field is an array that contains all the specified elements. To specify an $all expression, use the following prototype: { : { $all: [ , ... ] } }

In your case, you're looking for an object "req.params.category" that has this value:

{"0":"1","1":"101","2":"1001"}

Try this:

// data declaringconst { category } = req.params// destructuring  const posts = await Post.find({ category: category }).sort({ date: -1 });

// It's the sameconst posts = await Post.find({ category: 
 { 
  "0": "1",
  "1": "101",
  "2": "1001"
 }
}).sort({ date: -1 })

Also, if finally posts equals to cursor , use .next() to converto to the final result.

posts.next() 

I hope it works for you. Greetings.

Solution 2:

I think this structure is not logical so I change my post body to:

{"_id":"5ea00ded0e94961c0445bd5f","category":[{"cat_id":2,"cat_name":"2"},{"cat_id":102,"cat_name":"102"}],"user":"5deeaeeb06f015576080a435","title":"test5","description":"description5","date":"2020-04-22T09:27:09.692Z","__v":0}

and my schema is:

constPostSchema=newmongoose.Schema({user: {
    type:mongoose.Schema.Types.ObjectId,
    ref:'user'
},title: {
    type:String,
    required:true
},description: {
    type:String,
    required:true
},category: [
    {
        cat_id:Number,
        cat_name:String
    }
],options: {},phone: {
    type:String,
},country: {
    type:String,
},city: {
    type:String,
},date: {
    type:Date,
    default:Date.now
}

});

but the problem it's i can`t find on my category array with this code:

router.get('/category/:category', async (req, res) => {
try {
    const posts = await Post.find({category: {cat_name: req.params.category}})
    if (!posts) {
        return res.status(404).json({ msg: 'Ads not found' });
    }
    console.log(posts)

    res.json(posts);

} catch (err) {
    console.error(err.message);
    if (err.kind === 'ObjectId') {
        return res.status(404).json({ msg: 'Ads not found' });
    }
    res.status(500).send('Server Error!');
}

});

this return empty array [], I don't know why!

when I get all posts in console log my result is:

{ category: [ [Object], [Object] ], _id: 5ea00ded0e94961c0445bd5f, user: 5deeaeeb06f015576080a435, title: 'test5', description: 'description5', date: 2020-04-22T09:27:09.692Z, __v: 0 }

Solution 3:

The problem was solved this way: link

But I'm still happy to share your experiences about content categorization

so my final get posts by category is:

router.get('/category/:category', async (req, res) => {
try {
    const posts = awaitPost.find({category: {$elemMatch: {cat_name: 'req.params.category'}}})
    if (!posts) {
        return res.status(404).json({ msg: 'Ads not found' });
    }
    console.log(posts)
    res.json(posts);

} catch (err) {
    console.error(err.message);
    if (err.kind === 'ObjectId') {
        return res.status(404).json({ msg: 'Ads not found' });
    }
    res.status(500).send('Server Error!');
}

});