Find nested embedded array with Mongoose/MongoDB

Dr_Birkin 0
Viewed 21

I have tried to filter out nested array elements inside a document, but nothing is showing.

Here is my schema:

//Product:
const productSchema = new mongoose.Schema(
  {
    productname: {
      type: String,
      required: [true, 'User must have a name'],
      unique: true,
      validate: {
        validator: function (str) {
          return validator.isAlphanumeric(str, 'en-US', { ignore: ' ' });
        },
        message: (props) => `${props.value} is not a valid username`,
      },
    },
    slug: String,
    price: {
      type: Number,
      required: [true, 'A product must have a price'],
    },
    description: {
      type: String,
      trim: true,
    },
    images: [String],
    variants: [Variant], //Schema
  },
  {
    id: false,
    timestamps: true,
    toJSON: { virtuals: true },
    toObject: { virtuals: true },
  }
);


//Variant:
const variantSchema = new mongoose.Schema(
  {
    // product: {
    //   type: mongoose.Schema.ObjectId,
    //   ref: 'Product',
    // },
    // size: {
    //   type: mongoose.Schema.ObjectId,
    //   ref: 'Size',
    // },
    // color: {
    //   type: mongoose.Schema.ObjectId,
    //   ref: 'Color',
    // },
    size: {
      type: String,
      enum: {
        values: [
          '35',
          '35.5',
          '36',
          '36.5',
          '37',
          '37.5',
          '38',
          '38.5',
          '39',
          '39.5',
          '40',
          '41',
          '41.5',
          '42',
          '42.5',
          '43',
          '44',
          '44.5',
          '45',
          '46',
          '46.5',
          '47',
          '47.5',
          '48',
          'S',
          'M',
          'L',
          'XL',
          'XXL',
          'XS',
          'Onesize',
        ],
        message: 'Please enter correct sizing format !',
      },
      required: [true, 'Please enter sizing !'],
    },
    color: { type: String, required: [true, 'Please enter color !'] },
    quantity: Number,
  },
  {
    id: false,
    toJSON: { virtuals: true },
    toObject: { virtuals: true },
  }
);

Note: variants is embedded so is exported as Schema.

So I'm trying to filter out variant with color Grey like in the pic: enter image description here

What I did was finding the product by slug and filtering using the color property inside variant.

const document = await Model.find({
 slug: req.params.slug,
 variants: {
  color: 'Grey'
 }
});

It shows me nothing, 0

I also tried with "variants.color" : "Grey" But this time it gives me all the result. So it seems filter didnt apply or simply not worked.

mongoose mongodb node.js
1 Answers

You don't need virtuals in this case. According to populate() documentation this could be achieved by "match" option.

The solution should be:

  const document = await Model.find({
    slug: req.params.slug
  }).populate("variants", {
    match: { color: "Grey" } // query for subdocument
  });
Ali Haneen0
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