Node.js Basics — Skipping and Limiting MongoDB Results
Tags: webdev, programming, node, javascript
Published: 2021-01-24 01:19:35

**Check out my books on Amazon at https://www.amazon.com/John-Au-Yeung/e/B08FT5NT62**

**Subscribe to my email list now at http://jauyeung.net/subscribe/**

Node.js is a popular runtime platform to create programs that run on it.

It lets us run JavaScript outside the browser.

In this article, we’ll look at how to start using Node.js to create programs.

### Limit the Number of Returned Results

We can limit the number of returned results by calling the `limit` method.

For example, we can write:

```
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 query = {};
    const sort = { length: -1 };
    const limit = 3;
    const cursor = testCollection.find(query).sort(sort).limit(limit);
    await cursor.forEach(console.dir);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);
```

We call the `limit` method with the `limit` to set the max number of results to 3.

Also, we can set the properties in the query object.

For example, we can write:

```
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 query = {};
    const options = {
      sort: { rating: -1 }, limit: 3
    }
    const cursor = testCollection.find(query, options);
    await cursor.forEach(console.dir);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);
```

We put the `limit` property in the `options` object instead of calling `limit` to limit the number of results.

We can call the `skip` method to skip the first number of results.

For example, we can write:

```
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 query = {};
    const sort = { length: 1 };
    const limit = 3;
    const skip = 3;
    const cursor = testCollection.find(query).sort(sort).limit(limit).skip(skip);
    await cursor.forEach(console.dir);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);
```

We use the `skip` method with the `limit` method to add pagination for the results.

We skip the amount of results to reach the given page.

And `limit` sets the max number of results per page.

### Conclusion

We can limit the number of results and skip some results with the MongoDB Node.js client.