Composing Software. An Exploration of Functional Programming and Object Composition in JavaScript

Eric Elliott

This book delves into functional programming and composition techniques in JavaScript, starting with core concepts like pure functions, shared state avoidance, and higher-order functions to build modular, maintainable code. Early chapters explore the fundamentals of functional programming, immutability, and its growing influence in the JavaScript community. You'll learn essential topics such as function composition, currying, and higher-order functions, as well as advanced concepts like abstract data types, functors, and monads. The book discusses the evolution of functional programming, its role in modern software development, and addresses challenges like the software crisis and composing with classes. You'll learn essential topics like object-oriented programming, focusing on factory functions, functional mixins, and object composition. You'll also understand why traditional classes complicate composition and discover strategies for creating custom data types, lenses, and transducers. The book also covers best practices, emphasizing clean, reusable code and avoiding anti-patterns like excessive mocking. By the end, you'll be ready to apply functional programming techniques to tackle complex design challenges and write more maintainable JavaScript code.