MEAN Stack Development MCQ 3

Question 1

Which of the following correctly describes a MongoDB 'replica set'?

Accepted Answer

A group of mongod instances maintaining the same dataset for redundancy

Answer

A replica set is a group of MongoDB servers that maintain the same data, providing redundancy and high availability through automatic failover.

Question 2

In Angular, what is a `Resolver` used for in routing?

Accepted Answer

To pre-fetch data before a route is activated

Answer

A Resolver pre-fetches data before the route is activated, ensuring the component has all required data when it initializes.

Question 3

What is the default behavior of Node.js's `EventEmitter` when an 'error' event is emitted with no listener?

Accepted Answer

An exception is thrown and the process may crash

Answer

If no listener handles the 'error' event on an EventEmitter, Node.js throws the error as an exception, potentially crashing the process.

Question 4

Which Express.js method is used to serve static files from a directory?

Accepted Answer

express.static()

Answer

express.static() is a built-in middleware that serves static assets like HTML, CSS, and images from a specified directory.

Question 5

What does the MongoDB `$lookup` aggregation stage perform?

Accepted Answer

Performs a left outer join with another collection

Answer

$lookup performs a left outer join to another collection in the same database, adding matched documents as an array field.

MEAN - Stack Development Practice Test