How to do pagination with a mongodb aggregate?

Question

While working on MongoDB.I have a problem with doing Pagination.When I'm trying to include Paginaiton with aggerate.I'm also trying to include facets in this.

My code: Just for doing search

app.get("/search", async(req, res) => {
    try {
        const text = req.query.text

      let result = await collection.aggregate([                    
            {
                '$search': {
                    'text': {
                        'query': `${text}`,
                        'path': 'title'
                    }
                }
            }
        ]).toArray();
        res.send(result)
    } catch (error) {
       console.error(error)
    }
})

This works for both search as well as pagination. like this, see, It doesn't require any optional request.query.page.

http://localhost:4000/search?text=mango
http://localhost:4000/search?text=mango?page=1

---

---

Now, I want to include the pagination with facets search as well...So,

server.get("/search", async(req, res) => {
    try {
        const key = req.query.key;
        const value = req.query.value; 
        const text = req.query.text;
        const page = req.query.page; //Page query create

    let result = await collection.aggregate([                    
            {
                '$search': {
                    'text': {
                        'query': `${text}`,
                        'path': 'title'
                    }
                }
            },
            {
                '$match': {
                    [key]: `${value}`
                }
            }
        ]).toArray();
        res.send(result)

    } catch (error) {
       console.error(error)
    }
})

work for this: without no.of Pages

http://localhost:4000/search?text=Mango&key=Brand&value=rasna

Doesn't work for Pagination:

http://localhost:4000/search?text=Mango&key=Brand&value=rasna&page=2

where I'm wrong here? Do I need to create any additional function to make this works or Something else?

Answer 1

you can use both $skip and $limit aggregation pipelines to achieve this purpose. imagine that we want to have only 20 items per page. so our code looks like this:

    server.get("/search", async(req, res) => {
    try {
        const key = req.query.key;
        const value = req.query.value; 
        const text = req.query.text;
        const page = req.query.page - 1; //We subtract one because we don't want skip first twenty items in first page

    let result = await collection.aggregate([                    
            {
                '$search': {
                    'text': {
                        'query': `${text}`,
                        'path': 'title'
                    }
                }
            },
            {
                '$match': {
                    [key]: `${value}`
                }
            },
            { $skip: page * 20 },
            { $limit: 20 }
        ]).toArray();
        res.send(result)

    } catch (error) {
       console.error(error)
    }
})