The expression Math.round(-20.51) returns the value -21.
The Math.round() function in JavaScript is used to round a number to the nearest whole number. When applied to -20.51, it rounds the number to the nearest integer value. Since -20.51 is closer to -21 than to -20, the result is -21.
The http module in Node.js provides the necessary functionality to create an HTTP server or make HTTP requests as a client. It includes classes and methods to handle incoming HTTP requests, manage server connections, and construct HTTP responses.
MongoDB is a NoSQL database management system (DBMS). It is classified as a document-oriented database, which falls under the wider category of NoSQL databases.
In AngularJS (not to be confused with Angular), the angular.forEach function is used to iterate over elements in an array or object. It invokes the specified iterator function for each item in the collection.
The _id field in MongoDB is a unique key that is added automatically to each document in a collection. It acts as the document's main key and gives it a special identification inside the collection.
A Node.js project's locally installed modules are listed using the $ npm ls command. The installed modules and their dependencies are shown in detail.