MongoDB Node.JS driver: create, append, and update documents with arrays

Question

I am looking to achieve the following operations with the MongoDB Node.JS driver, could this be performed with an optimal approach? There are three possible operations required: create, append, and update.

1. Create the following document.

{
    "_id": "hello_world_cluster",
        "items": [
            {
                "item_name": "my_item_one",
                "first_seen": 1000,
                "last_seen": 1000,
                "logic": true
            }
        ]
}

2. Append new items to an array.

{
    "_id": "hello_world_cluster",
        "items": [
            {
                "item_name": "my_item_one",
                "first_seen": 1000,
                "last_seen": 1000,
                "logic": true
            },
            {
                "item_name": "my_item_two",
                "first_seen": 2000,
                "last_seen": 2000,
                "logic": true
            },
            {
                "item_name": "my_item_three",
                "first_seen": 3000,
                "last_seen": 3000,
                "logic": true
            }
        ]
}

3. Update items that are found in an array.

{
    "_id": "hello_world_cluster",
        "items": [
            {
                "item_name": "my_item_one",
                "first_seen": 1000,
                "last_seen": 4000,
                "logic": false
            },
            {
                "item_name": "my_item_two",
                "first_seen": 2000,
                "last_seen": 2000,
                "logic": true
            },
            {
                "item_name": "my_item_three",
                "first_seen": 3000,
                "last_seen": 3000,
                "logic": true
            }
        ]
}

Answer 1

I drafted some sample code for you:

 const { MongoClient } = require('mongodb'); async function main() { /** * Connection URI. Update <username>, <password>, and <your-cluster-url> to reflect your cluster. */ const uri = "mongodb+srv://<username>:<password>@<your-cluster-url>/test?retryWrites=true&w=majority"; /** * The Mongo Client you will use to interact with your database */ const client = new MongoClient(uri, { useUnifiedTopology: true }); try { // Connect to the MongoDB cluster await client.connect(); // Make the appropriate DB calls // Create a new document await createDocument(client); // Append new items to the items array await appendNewItemsToArray(client); // Update items in the items array await updateItemsInArray(client); } finally { // Close the connection to the MongoDB cluster await client.close(); } } main().catch(console.error); async function createDocument(client) { const result = await client.db("NameOfYourDb").collection("NameOfYourCollection").insertOne({ "_id": "UniqueId1", "items": [ { "item_name": "my_item_one", "first_seen": 1000, "last_seen": 1000, "logic": true } ] }); console.log(`New document created with the following id: ${result.insertedId}`); } async function appendNewItemsToArray(client) { const result = await client.db("NameOfYourDb").collection("NameOfYourCollection").updateOne( { "_id": "UniqueId1" }, { $push: { items: { $each: [ { "item_name": "my_item_two", "first_seen": 2000, "last_seen": 2000, "logic": true }, { "item_name": "my_item_three", "first_seen": 3000, "last_seen": 3000, "logic": true }] } } }); console.log(`${result.matchedCount} document(s) matched the query criteria.`); console.log(`${result.modifiedCount} document(s) was/were updated.`); } async function updateItemsInArray(client) { const result = await client.db("NameOfYourDb").collection("NameOfYourCollection").updateOne( { "_id": "UniqueId1", "items.item_name": "my_item_one" }, { $set: { "items.$.logic": false, "items.$.last_seen": 4000 } } ); console.log(`${result.matchedCount} document(s) matched the query criteria.`); console.log(`${result.modifiedCount} document(s) was/were updated.`); }

One important thing to note: The _id needs to be unique for every document within a collection. You do not have to manually create the _id. If you omit _id from the document, the driver will automatically create one for you.

This code is based on code from my blog series. Some helpful links for you:

• https://www.mongodb.com/blog/post/quick-start-nodejs-mongodb--how-to-get-connected-to-your-database
  • https://www.mongodb.com/blog/post/quick-start-nodejs--mongodb--how-to-create-documents
  • https://www.mongodb.com/blog/post/quick-start-nodejs--mongodb--how-to-update-documents

The code takes advantage of combining $push and $each. See https://docs.mongodb.com/manual/reference/operator/update/push/#example-push-each for more details on that.

The code also takes advantage of the positional $ operator. See https://docs.mongodb.com/manual/reference/operator/update/positional/ for more details on that.