30 Questions
Which of the following is NOT a property of Node.js?
Multi-threaded
Which of the following is true about callbacks in Node.js?
They are invoked asynchronously
What is the purpose of the event loop in Node.js?
To execute callback functions
What is the data type used for representing all numbers in JavaScript?
Floating-point
Which of the following data types in JavaScript evaluate to false?
null
Which of the following is a correct way to declare a constant in JavaScript?
Using uppercase letters for variable declarations
Which of the following is a correct way to add two strings together in JavaScript?
Using the + operator
What does the function JSON.parse do in JavaScript?
Converts a JSON string to an object
Which of the following is a common problem with blocking I/O in server-side applications?
Low efficiency in handling orders
What is one of the previous solutions to address blocking I/O problems?
Increase the number of simultaneous connections
What is one of the evolved solutions to address blocking I/O problems?
Increase client libraries
What is the main drawback of blocking I/O in web applications?
Time-consuming and low efficiency
Which method is used to group documents in the 'aggregateRestaurants' function?
$group
What is the purpose of the $sum operator in the 'aggregateRestaurants' function?
To calculate the sum of a numeric field
What does the 'toArray' method do in the 'aggregateRestaurants' function?
Converts the aggregated data into an array
In which collection is the 'aggregateRestaurants' function performing the aggregation?
restaurant
Which of the following statements is true about the switch statement in JavaScript?
The switch statement executes the code block that matches the value of the expression.
What is the purpose of the 'while' loop in JavaScript?
To execute a block of code as long as a specified condition is true.
Which of the following statements is true about querying by a field in an array in MongoDB?
The query returns documents where the specified field in the array matches the specified value.
What does the $or operator do in MongoDB?
The $or operator returns documents that match any of the specified conditions.
What is the purpose of the 'aggregateRestaurants' function?
The purpose of the 'aggregateRestaurants' function is to perform aggregation operations on the 'restaurant' collection in the database.
What does the $group operator do in the 'aggregateRestaurants' function?
The $group operator is used to group documents together based on a specified key and perform aggregation functions on the grouped data.
What is the purpose of the $sum operator in the 'aggregateRestaurants' function?
The purpose of the $sum operator is to calculate the sum of a specified field in the grouped documents.
What does the $match operator do in the 'aggregateRestaurants' function?
The $match operator is used to filter documents based on specified criteria.
What is the purpose of the 'toArray' method in the 'aggregateRestaurants' function?
The purpose of the 'toArray' method is to convert the result of the aggregation operation into an array of documents.
What is one of the common problems with blocking I/O in server-side applications?
One of the common problems with blocking I/O in server-side applications is that it can lead to poor performance and scalability.
What is the main drawback of blocking I/O in web applications?
The main drawback of blocking I/O in web applications is that it can cause the application to become unresponsive and slow.
What is the purpose of the event loop in Node.js?
The purpose of the event loop in Node.js is to handle asynchronous operations and ensure non-blocking I/O.
In which collection is the 'aggregateRestaurants' function performing the aggregation?
The 'aggregateRestaurants' function is performing the aggregation on the 'restaurant' collection.
What is a correct way to declare a constant in JavaScript?
A correct way to declare a constant in JavaScript is using the 'const' keyword followed by the variable name and its initial value.
Learn about numbers, NaN, and boolean data types in this quiz. Understand the behavior of dividing a number by zero and how to convert strings to numbers. Discover the values that evaluate to false in boolean data types.
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