Add the tag `"urgent"` to the `tags` array of ticket `_id: 1`. Return the ticket.

Problem Statement

<p>Add the tag <code>"urgent"</code> to the <code>tags</code> array of ticket <code>_id: 1</code>. Return the ticket.</p>

Examples

Input: tickets collection: +-----+-----------------+----------------+ | _id | subject | tags | +-----+-----------------+----------------+ | 1 | Login Bug | ["bug","auth"] | | 2 | Feature Request | ["feature"] | +-----+-----------------+----------------+

Output: +-----+-----------+-------------------------+ | _id | subject | tags | +-----+-----------+-------------------------+ | 1 | Login Bug | ["bug","auth","urgent"] | +-----+-----------+-------------------------+

Explanation: The target document is modified according to the update operators and the updated document is returned.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Use db.<collection>.find(<filter>) to query the documents in the collection. 💡 Hint 2: Pass an empty object {} to retrieve all documents, or specify key-value pairs for exact matching. 💡 Hint 3: Chain .toArray() to resolve the MongoDB cursor into a JavaScript array: return db.<collection>.find(...).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Push to Array ($push)", we query the MongoDB document store. The goal is to add the tag `"urgent"` to the `tags` array of ticket `_id: 1`. return the ticket. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

Identify Target Collection: Access the collection through the db instance.
Construct Query / Pipeline: Build the query filter with appropriate comparison operators.
Resolve Cursor: Invoke .toArray() to transform the query cursor into the required array of documents.

Optimal Implementation (MongoDB)

function solve(db) {
  db.tickets.updateOne({ _id: 1 }, { $push: { tags: "urgent" } });
  return db.tickets.findOne({ _id: 1 });
}

Complexity Analysis

Time Complexity O(N) collection scan (O(log N) if index is present on filtered fields).

Space Complexity O(K) where K is the number of returned documents in memory.

Key Considerations & Edge Cases

Empty Collections: If no documents match, the query cleanly returns an empty array [].
Missing / NULL Fields: Missing fields in documents are handled safely without throwing runtime exceptions.
Type Coercion: BSON types (ObjectId, Numbers, Strings) are compared strictly according to MongoDB specifications.

Push to Array ($push)

Easy

Add the tag "urgent" to the tags array of ticket _id: 1. Return the ticket.

Example Scenarios

1Example 1

Input:

tickets collection

_id	subject	tags
1	Login Bug	["bug","auth"]
2	Feature Request	["feature"]

Output:

_id	subject	tags
1	Login Bug	["bug","auth","urgent"]

Explanation:

The target document is modified according to the update operators and the updated document is returned.

MongoDB Editor

Loading Editor...

Query Results (JSON)

Run your MongoDB code to see results here.