Functional programming means using functions to the best effect for creating clean and maintainable software. More specifically, functional programming is a set of approaches to coding, usually described as a programming paradigm.
The definition of a pure function is: The function always returns the same result if the same arguments are passed in. It does not depend on any state, or data, change during a program’s execution. It must only depend on its input arguments.
Major benefits of using pure functions is they are immediately testable. They will always produce the same result if you pass in the same arguments. They also makes maintaining and refactoring code much easier.
An immutable object (unchangeable object) is an object whose state cannot be modified after it is created.
Referential transparency and referential opacity are properties of parts of computer programs. … An expression is called referentially transparent if it can be replaced with its corresponding value (and vice-versa) without changing the program’s behavior.
A module is a software component or part of a program that contains one or more routines. One or more independently developed modules make up a program. An enterprise-level software application may contain several different modules, and each module serves unique and separate business operations.Modules make a programmer’s job easy by allowing the programmer to focus on only one area of the functionality of the software application. Modules are typically incorporated into the program (software) through interfaces.
The require() method is used to load and cache JavaScript modules. So, if you want to load a local, relative JavaScript module into a Node. js application, you can simply use the require() method.
The first thing you do to get access to module features is export them. This is done using the export statement. You can export functions, var , let , const , and — as we’ll see later — classes. They need to be top-level items; you can’t use export inside a function, for example.