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Specify Which Fields to Return with MongoDB

We can specify the fields that we want to return for each entry/.

For example, we can wrote:

const { MongoClient } = require('mongodb');
const connection = "mongodb://localhost:27017";
const client = new MongoClient(connection);

async function run() {
  try {
    await client.connect();
    const testCollection = await client.db("test").collection('test');
    await testCollection.deleteMany({})
    const result = await testCollection.insertMany([
      { "_id": 1, "name": "apples", "qty": 5, "rating": 3 },
      { "_id": 2, "name": "bananas", "qty": 7, "rating": 1 },
      { "_id": 3, "name": "oranges", "qty": 6, "rating": 2 },
      { "_id": 4, "name": "avocados", "qty": 3, "rating": 5 },
    ]);
    console.log(result)
    const projection = { name: 1 };
    const cursor = testCollection.find().project(projection);
    await cursor.forEach(console.dir);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);

We call the project method with an object that has the keys that we want to include in the keys.

The value is 1 means we include the given property in the result.

The _id field is returned automatically by default.

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