Not getting specified data on aggregation

[Diwash_Tiwari]

Hi there, as a new in MongoDB, I’m trying to get the specified data using aggregation but I’m getting an error even when I tried other ways still i got an empty array …

I only need the items obj that matches the productId

const item = await Cart.aggregate([
          {
            $project: {
              items: {
                $filter: {
                  input: "$items",
                  as: "item",
                  cond: { $gte: ["$$items.productId", productId] },
                },
              },
            },
          },
        ]);

[Akshat_Gupta3 (Akshat Gupta)]

Hi Diwash,
You are using $gte operator instead of $eq, also you are passing the wrong variable in the array. Here is the corrected pipeline stage -

{
    $project:
      {
        items: {
          $filter: {
            input: "$items",
            as: "item",
            cond: {
              $eq: ["$$item.productId", productId],
            },
          },
        },
      }
  }

[Diwash_Tiwari]

Thanks @Akshat_Gupta3

but now I’m getting an empty array and I only need the obj that matches the productId

[ { _id: new ObjectId('65eeafd35fa4289f83fee325'), items: [] } ]

[Akshat_Gupta3 (Akshat Gupta)]

Can you please share how you are passing the productId?

[Diwash_Tiwari]

well I m extracting it from the body like this

   const { user, item } = req.body;

    const { productId } = item;

    const product = await Cart.aggregate([
      {
        $project: {
          items: {
            $filter: {
              input: "$items",
              as: "item",
              cond: {
                $eq: ["$$item.productId", productId],
              },
            },
          },
        },
      },
    ]);

[Diwash_Tiwari]

Thanks @Akshat_Gupta3 bro
it was my mistake I was providing the id as a string
Thanks for the guidance