Book Image

Mastering JavaScript Functional Programming - Second Edition

By : Federico Kereki
Book Image

Mastering JavaScript Functional Programming - Second Edition

By: Federico Kereki

Overview of this book

Functional programming is a paradigm for developing software with better performance. It helps you write concise and testable code. To help you take your programming skills to the next level, this comprehensive book will assist you in harnessing the capabilities of functional programming with JavaScript and writing highly maintainable and testable web and server apps using functional JavaScript. This second edition is updated and improved to cover features such as transducers, lenses, prisms and various other concepts to help you write efficient programs. By focusing on functional programming, you’ll not only start to write but also to test pure functions, and reduce side effects. The book also specifically allows you to discover techniques for simplifying code and applying recursion for loopless coding. Gradually, you’ll understand how to achieve immutability, implement design patterns, and work with data types for your application, before going on to learn functional reactive programming to handle complex events in your app. Finally, the book will take you through the design patterns that are relevant to functional programming. By the end of this book, you’ll have developed your JavaScript skills and have gained knowledge of the essential functional programming techniques to program effectively.
Table of Contents (17 chapters)
Technical Requirements

Partial application

The second transformation that we will be considering lets you fix some of the parameters of the function, creating a new function that will receive the rest of them. Let's make this clear with a nonsense example. Imagine you have a function with five parameters. You might want to fix the second and fifth parameters, and partial application would then produce a new version of the function that fixed those two parameters but left the other three open for new calls. If you called the resulting function with the three required arguments, it would produce the correct answer, by using the original two fixed parameters plus the newly provided three.

The idea of specifying only some of the parameters in function application, producing a function of the remaining parameters, is called projection: you are said to be projecting the function onto the remaining arguments...