Functional programming is a programming paradigm – a style of building the structure and elements of computer programs – that treats computation as the evaluation of mathematical functions, and avoids changing state and mutable data. JavaScript supports this style of programming, even though it’s not a functional programming language in the strictest sense. Below are some fundamental concepts of functional programming:
1. Pure functions: A pure function is a function where the return value is only determined by its inputs, without observable side effects or dependencies on global state. This is the fundamental unit of work in functional programming.
1. Immutability: In functional programming, state is not modified after it’s created. If you want to change an object, you don’t update the object itself. Instead, you create a copy of the object, and modify the copy.
1. Higher-order functions: These are functions which take in other functions as arguments, return a function as a result, or do both! JavaScript’s Array.prototype.map, Array.prototype.filter and Array.prototype.reduce are examples of higher order functions.
1. Function composition: The process of combining two or more functions to produce a new function. This is central to functional programming.
1. Recursion: Using recursion in functional programming allows for certain tasks to be defined in terms of themselves. It gives the ability to make clean and intuitive solutions for complex programming tasks like tree-
traversal.
1. First-class functions: Functional programming languages, like JavaScript, support passing functions as arguments to other functions, returning them as the values from other functions, and assigning them to variables or storing them in data structures.
1. Currying: It’s a technique in which a function with more than one parameter is transformed into a new function that takes just one parameter, and for subsequent parameters, returns a new function that takes the next parameter, and so forth.
By incorporating these features and principles, functional programming aims to make the effects of operations more predictable and the code more readable and maintainable.
