Functional Javascript

How can you overcome JavaScript language oddities and unsafe features? With this book, you’ll learn how to create code that’s beautiful, safe, and simple to understand and test by using JavaScript’s functional programming support. Author Michael Fogus shows you how to apply functional-style concepts with Underscore.js, a JavaScript library that facilitates functional programming techniques. Sample code is available on GitHub at https://github.com/funjs/book-source. Fogus helps you think in a functional way to help you minimize complexity in the programs you build. If you’re a JavaScript programmer hoping to learn functional programming techniques, or a functional programmer looking to learn JavaScript, this book is the ideal introduction. Use applicative programming techniques with first-class functions Understand how and why you might leverage variable scoping and closures Delve into higher-order functions—and learn how they take other functions as arguments for maximum advantage Explore ways to compose new functions from existing functions Get around JavaScript’s limitations for using recursive functions Reduce, hide, or eliminate the footprint of state change in your programs Practice flow-based programming with chains and functional pipelines Discover how to code without using classes

Summary Functional Programming in JavaScript teaches JavaScript developers functional techniques that will improve extensibility, modularity, reusability, testability, and performance. Through concrete examples and jargon-free explanations, this book teaches you how to apply functional programming to real-life development tasks Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications. About the Technology In complex web applications, the low-level details of your JavaScript code can obscure the workings of the system as a whole. As a coding style, functional programming (FP) promotes loosely coupled relationships among the components of your application, making the big picture easier to design, communicate, and maintain. About the Book Functional Programming in JavaScript teaches you techniques to improve your web applications - their extensibility, modularity, reusability, and testability, as well as their performance. This easy-to-read book uses concrete examples and clear explanations to show you how to use functional programming in real life. If you're new to functional programming, you'll appreciate this guide's many insightful comparisons to imperative or object-oriented programming that help you understand functional design. By the end, you'll think about application design in a fresh new way, and you may even grow to appreciate monads! What's Inside High-value FP techniques for real-world uses Using FP where it makes the most sense Separating the logic of your system from implementation details FP-style error handling, testing, and debugging All code samples use JavaScript ES6 (ES 2015) About the Reader Written for developers with a solid grasp of JavaScript fundamentals and web application design. About the Author Luis Atencio is a software engineer and architect building enterprise applications in Java, PHP, and JavaScript. Table of Contents PART 1 THINK FUNCTIONALLY Becoming functional Higher-order JavaScript PART 2 GET FUNCTIONAL Few data structures, many operations Toward modular, reusable code Design patterns against complexity PART 3 ENHANCING YOUR FUNCTIONAL SKILLS Bulletproofing your code Functional optimizations Managing asynchronous events and data

Functional-Light JavaScript is a balanced, pragmatic exploration of Functional Programming in JavaScript.Functional Programming (FP) is an incredibly powerful paradigm for structuring code that yields more robust, verifiable, and readable programs. If you've ever tried to learn FP but struggled with terms like "monad", mathematical concepts like category theory, or symbols like (lambda), you're not alone.Functional-Light programming distills the most vital aspects of FP-function purity, value immutability, composition, and more!-down to approachable JavaScript patterns. Rather than the all-or-nothing dogmatism often encountered in FP, this book teaches you how to improve your programs line by line.

All software design is composition: the act of breaking complex problems down into smaller problems and composing those solutions. Most developers have a limited understanding of compositional techniques. It's time for that to change.In "Composing Software", Eric Elliott shares the fundamentals of composition, including both function composition and object composition, and explores them in the context of JavaScript. The book covers the foundations of both functional programming and object oriented programming to help the reader better understand how to build and structure complex applications using simple building blocks.You'll learn: Functional programmingObject compositionHow to work with composite data structuresClosuresHigher order functionsFunctors (e.g., array.map)Monads (e.g., promises)TransducersLensesAll of this in the context of JavaScript, the most used programming language in the world. But the learning doesn't stop at JavaScript. You'll be able to apply these lessons to any language. This book is about the timeless principles of software composition and its lessons will outlast the hot languages and frameworks of today. Unlike most programming books, this one may still be relevant 20 years from now.This book began life as a popular blog post series that attracted hundreds of thousands of readers and influenced the way software is built at many high growth tech startups and fortune 500 companies

Explore the functional programming paradigm and the different techniques for developing better algorithms, writing more concise code, and performing seamless testing Key FeaturesExplore this second edition updated to cover features like async functions and transducers, as well as functional reactive programmingEnhance your functional programming (FP) skills to build web and server apps using JavaScriptUse FP to enhance the modularity, reusability, and performance of appsBook Description 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. What you will learnSimplify JavaScript coding using function composition, pipelining, chaining, and transducingUse declarative coding as opposed to imperative coding to write clean JavaScript codeCreate more reliable code with closures and immutable dataApply practical solutions to complex programming problems using recursionImprove your functional code using data types, type checking, and immutabilityUnderstand advanced functional programming concepts such as lenses and prisms for data accessWho this book is for This book is for JavaScript developers who want to enhance their programming skills and build efficient web applications. Frontend and backend developers who use various JavaScript frameworks and libraries like React, Angular, or Node.js will also find the book helpful. Working knowledge of ES2019 is required to grasp the concepts covered in the book easily.

Master Functional Programming techniques with this comprehensive guide for writing cleaner, safer, high-performing JavaScript codes About This Book Become proficient and skilled with Functional Programming in JavaScript to solve real-world development problems Successfully apply Functional Programming concepts and techniques to everyday JavaScript programming Bring modularity, reusability, testability, and performance to your web apps Who This Book Is For If you are a JavaScript developer and want to apply functional programming techniques, then this book is for you. Only a basic knowledge of the concepts of functional programming is required for this book. What You Will Learn Create more reliable code with closures and immutable data Convert existing methods into pure functions, and loops into recursive methods Develop more powerful applications with currying and function composition Separate the logic of your system from implementation details Implement composition and chaining techniques to simplify coding Use functional programming techniques where it makes the most sense In Detail Functional programming is a programming paradigm for developing software using functions. Learning to use functional programming is a good way to write more concise code, with greater concurrency and performance. The JavaScript language is particularly suited to functional programming. This book provides comprehensive coverage of the major topics in functional programming with JavaScript to produce shorter, clearer, and testable programs. You'll delve into functional programming; including writing and testing pure functions, reducing side-effects, and other features to make your applications functional in nature. Specifically, we'll explore techniques to simplify coding, apply recursion for loopless coding, learn ways to achieve immutability, implement design patterns, and work with data types. By the end of this book, you'll have developed the JavaScript skills you need to program functional applications with confidence. Style and approach This book takes an easy-to-follow, step-by-step tutorial approach. You will make the most of JavaScript programming with a focus on the progression of functional programming techniques, styles, and detailed information about JavaScript libraries.

In this book, you will find how to use JavaScript as a functional programming language. It turns out that JavaScript has everything it needs to be used as a functionallanguage. We just have to remove features from the language starting with the 'this' keyword. Functions are values. Functions can operate on other functions. Inner functions can access variables from the outer functions even after the outer functions have executed. Functional programming makes code easier to read, understand, test, and debug. Here are some of the things you will learn: How to disable 'this' and enable immutable data objects using a linter How to work with immutable objects and collections How to do data transformations using core operations like filter, map, sort, or reduce How to use statements like if and switch in a functional way How to create pipelines and use currying to pass additional data How to create and use functors and monads How to work with promises and observables Understand the Elm Architecture

Unlock the powers of functional programming hidden within JavaScript to build smarter, cleaner, and more reliable web apps About This Book Write powerful code with the high-level functions that JavaScript offers Discover what functional programming is, why it's effective, and how it's used in JavaScript Understand and optimize JavaScript's hidden potential as a true functional language Who This Book Is For If you are a JavaScript developer interested in learning functional programming, looking for the quantum leap toward mastering the JavaScript language, or just want to become a better programmer in general, then this book is ideal for you. This guide is aimed at programmers, involved in developing reactive frontend apps, server-side apps that wrangle with reliability and concurrency, and everything in between. What You Will Learn Get a run through of the basic JavaScript language constructs Code using the powerful object-oriented feature in JavaScript Master DOM manipulation, cross-browser strategies, and ES6 Understand the basic concurrency constructs in Javascript and best performance strategies Harness the power of patterns for tasks ranging from application building to code testing Build large-scale apps seamlessly with the help of reactive patterns Explore advanced design patterns, including dependency injection Develop more powerful applications with currying and function composition Create more reliable code with closures and immutable data In Detail JavaScript is a high-level, dynamic, untyped, lightweight, and interpreted programming language and functional programming is a style that emphasizes and enables smarter code that minimizes complexity and increases modularity. It's a way of writing cleaner code through clever ways of mutating, combining, and using functions. And JavaScript provides an excellent medium for this approach. By learning how to expose JavaScript's true identity as a functional language, we can implement web apps that are more powerful, easier to maintain and more reliable. The java script: Functional Programming for JavaScript Developers course will take you on a journey to show how functional programming when combined with other techniques makes JavaScript programming more efficient. The first module Mastering JavaScript, stress on practical aspects of Javascript development like—Functions and Closures, Runtime debugging techniques, project layout, events and DOM processing, build tools, Object-oriented patterns, isomorphism—everything that a modern Javascript project would need. The second module, Mastering JavaScript Design Patterns - Second Edition, will explore how design patterns can help you improve and organize your JavaScript code. You'll get to grips with creational, structural, and behavioral patterns as you discover how to put them to work in different scenarios. This updated edition will also delve into reactive design patterns and microservices as they are a growing phenomenon in the world of web development. It will also show you some advanced patterns, including dependency injection and live post processing. The third module, Functional Programming in JavaScript, will help you to write real-world applications by utilizing a wide range of functional techniques and styles. It explores the core concepts of functional programming common to all functional languages, with examples of their use in JavaScript. Style and approach This course will begin with providing insights and practical tips on advanced JavaScript features to build highly scalable web and mobile system and move on to some design patterns with JavaScript. Finally, the course ends with presenting the functional programming techniques and styles in JavaScript.