Functions in JavaScript provide modularity and reusability of code to the applications developed. They combine many instructions into a single line of code. In this learning sprint, you will learn to declare and use functions in a program.

"Modular programming is a software design technique that emphasizes on separating the functionality of a program into independent, interchangeable modules. Each of these modules contain everything necessary to execute only one aspect of the desired functionality. This learning sprint will enable you to work with the different types of modules provided in the Node.js environment, like the inbuilt and user-defined modules. "

Asynchronous programming is a technique that enables a program to start a potentially long-running task, and work seamlessly till it has has finished. It continues to be responsive to other events even while the task is running. Once the task is completed, the program is presented with the result. In this learning sprint, you will learn to write asynchronous programs.

"In any programming language be it Java or C, you need to deal with several file operations, based on the business needs. To perform these operations seamlessly, Node.js provides a specific inbuilt module called the File System Module to help potential developers. A Node.js File System Module handles file operations like creating, reading, deleting and updating a file. All file system operations can have synchronous and asynchronous forms depending upon their users' requirements. In this learning sprint, you will learn how to read and write on a file both synchronously and asynchronously."

Dealing with errors involves two very different processes; error handling and debugging. Error handling is a combination of coding and methodology that allows your program to anticipate its users and the errors. Errors, bugs, and debugging are therefore, a part of a programmer's life. This learning sprint, will enable you to handle error using exception handling mechanisms and debug a code using the inbuilt debugger tools of Chrome and VSCode.

Testing is essential to identify mistakes. Some mistakes might be less important, while some are expensive or could be life-threatening. It is therefore crucial, to test everything that is produced because things can go wrong; humans can make mistakes at any time. Testing is important since it discovers defects/bugs before delivery to the client. It guarantees quality of both the service and software. It makes a software more reliable and easy to use. A thoroughly tested software ensures a reliable and high-performance software operation. In this learning sprint, you will learn how to test JavaScript file using Mocha and Chai testing library.