Functional JavaScript. Introducing Functional Programming with Underscore.js (e-book) Leśnica

How can you overcome JavaScript language oddities and unsafe features? With this book, youll learn how to create code thats beautiful, safe, and simple to understand and test by using JavaScripts 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 youre 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 JavaScripts 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 Spis treści: Functional JavaScript Dedication Foreword by Jeremy Ashkenas Foreword by Steve Vinoski Preface What Is Underscore? Getting Underscore Using Underscore The Source Code for Functional JavaScript Running the Code in This Book Notational Conventions Whom Functional JavaScript Is Written For A Roadmap for Functional JavaScript Conventions Used in This Book Using Code Examples Safari Books Online How to Contact Us Acknowledgments 1. Introducing Functional JavaScript The Case for JavaScript Some Limitations of JavaScript Getting Started with Functional Programming Why Functional Programming Matters Functions as Units of Abstraction Encapsulation and Hiding Functions as Units of Behavior Data as Abstraction A Taste of Functional JavaScript On Speed The Case for Underscore Summary 2. First-Class Functions and Applicative Programming Functions as First-Class Things JavaScripts Multiple Paradigms Imperative programming Prototype-based object-oriented programming Metaprogramming Applicative Programming Collection-Centric Programming Other Examples of Applicative Programming reduceRight find reject all any sortBy, groupBy, and countBy Defining a Few Applicative Functions Data Thinking Table-Like Data Summary 3. Variable Scope and Closures Global Scope Lexical Scope Dynamic Scope JavaScripts Dynamic Scope Function Scope Closures Simulating Closures Free variables Shadowing Using Closures Closures as an Abstraction Summary 4. Higher-Order Functions Functions That Take Other Functions Thinking About Passing Functions: max, finder, and best Tightening it up a bit More Thinking About Passing Functions: repeat, repeatedly, and iterateUntil Use functions, not values I said, Use functions, not values Functions That Return Other Functions Capturing Arguments to Higher-Order Functions Capturing Variables for Great Good Take care when mutating values A Function to Guard Against Nonexistence: fnull Putting It All Together: Object Validators Summary 5. Function-Building Functions The Essence of Functional Composition Mutation Is a Low-Level Operation Currying To Curry Right, or To Curry Left Automatically Currying Parameters Building new functions using currying Currying three parameters to implement HTML hex color builders Currying for Fluent APIs The Disadvantages of Currying in JavaScript Partial Application Partially Applying One and Two Known Arguments Partially Applying an Arbitrary Number of Arguments Partial Application in Action: Preconditions Stitching Functions End-to-End with Compose Pre- and Postconditions Using Composition Summary 6. Recursion Self-Absorbed Functions (Functions That Call Themselves) Graph Walking with Recursion Depth-First Self-Recursive Search with Memory Tail (self-)recursion Recursion and Composing Functions: Conjoin and Disjoin Codependent Functions (Functions Calling Other Functions That Call Back) Deep Cloning with Recursion Walking Nested Arrays Too Much Recursion! Generators The Trampoline Principle and Callbacks Recursion Is a Low-Level Operation Summary 7. Purity, Immutability, and Policies for Change Purity The Relationship Between Purity and Testing Separating the Pure from the Impure Property-Testing Impure Functions Purity and the Relationship to Referential Transparency Purity and the Relationship to Idempotence Immutability If a Tree Falls in the Woods, Does It Make a Sound? Immutability and the Relationship to Recursion Defensive Freezing and Cloning Observing Immutability at the Function Level Observing Immutability in Objects Objects Are Often a Low-Level Operation Policies for Controlling Change Summary 8. Flow-Based Programming Chaining A Lazy Chain Promises Pipelining Data Flow versus Control Flow Finding a Common Shape A Function to Simplify Action Creation Summary 9. Programming Without Class Data Orientation Building Toward Functions Mixins Core Prototype Munging Class Hierarchies Changing Hierarchies Flattening the Hierarchy with Mixins New Semantics via Mixin Extension New Types via Mixin Mixing Methods Are Low-Level Operations }).call(Finis); A. Functional JavaScript in the Wild Functional Libraries for JavaScript Functional JavaScript Underscore-contrib RxJS Bilby allong.es Other Functional Libraries Functional Programming Languages Targeting JavaScript ClojureScript CoffeeScript Roy Elm B. Annotated Bibliography Papers/Books/Blog Posts/Talks Presentations Blog Posts Journal Articles Index About the Author Colophon Copyright