book

JavaScript: Functional Programming for JavaScript Developers

by Ved Antani, Simon Timms, Dan Mantyla

August 2016

Intermediate to advanced

635 pages

14h 5m

English

Packt Publishing

Read now

Unlock full access

What this learning path covers
Downloading theexample codeErrataPiracyQuestions

A little bit of history
An overview of JavaScriptCommentsVariablesConstantsNumberStringUndefined valuesBooleansThe instanceof operatorDate objectsThe + operatorThe ++ and -- operatorsBoolean operatorsEqualityStrict equality using ===Weak equality using ==JavaScript typesAutomatic semicolon insertionJavaScript style guideWhitespacesParentheses, line breaks, and bracesQuotesEnd of lines and empty linesType checkingType castingConditional evaluationNamingThe eval() method is evilThe strict modeEnabling the strict mode for an existing code can break itPackage with careVariables must be declared in strict modeThe eval() function is cleaner in strict modeFeatures that are blocked in strict modeRunning JSHint
A function literalA function declaration
Global scopeLocal scopeFunction-level scope versus block-level scopeInline function expressionsBlock scopes
The this parameterInvocation as a functionInvocation as a methodInvocation as a constructorInvocation using apply() and call() methods
Anonymous functions while creating an objectAnonymous functions while creating a listAnonymous functions as a parameter to another functionAnonymous functions in conditional logic
Stylistic considerations
Regular expressions
Alternatives – OR
Understanding objectsBehavior of JavaScript objectsPrototypes
Unit testingTest-driven developmentBehavior-driven development
Syntax errorsUsing strictRuntime exceptionsConsole.log and assertsChrome DevTools
Shims or polyfills
Block scopingDefault parametersSpread and restDestructuringObject literalsTemplate literalsMaps and SetsSymbolsIteratorsFor..of loopsArrow functions
DOMAccessing DOM elementsAccessing specific nodes
An asynchronous evented-model in a browser
Creating modules
Installing packages
JavaScript profilingThe CPU profileThe Timeline view
The road to JavaScriptThe early daysA pauseThe way of GMailJavaScript everywhere
Chunks of code
Abstract factoryImplementation
Implementation
Implementation
ImplementationDisadvantages
Implementation
AdapterImplementation
Implementation
ExampleImplementation
Implementation
Implementation
Implementation
Implementation
Chain of responsibilityImplementation
Command messageInvokerReceiver
ExampleImplementation
ImplementationECMAScript 2015 iterators
Implementation
Implementation
Implementation
Implementation
Implementation
Implementation
Functional functions are side-effect-free
Implementation
Implementation
Implementation
Implementation
Implementation
Application state changes
First, some history
MVC code
MVP code
MVVM codeA better way to transfer changes between the model and the viewObserving view changes
Sending JavaScriptCombining filesMinificationContent Delivery Networks
jQueryd3
Back-offDegraded application behavior
What's a message anyway?CommandsEvents
Fan out and in
Message replayPipes and filtersVersioning messages
Façade
Service degradationMessage storageMessage replayIndempotence of message handling
The testing pyramid
Assert
Browser testingFaking the DOMWrapping the manipulation
Dependency injection
TypeScriptDecoratorsAsync/AwaitTyping
ClassesDefault parametersTemplate literalsBlock bindings with letIn production
Introduction
Imperative methods
Functional programming languagesWhat makes a language functional?AdvantagesCleaner codeModularityReusabilityReduced couplingMathematically correctFunctional programming in a nonfunctional worldIs JavaScript a functional programming language?
Self-invoking functions and closuresHigher-order functionsPure functionsAnonymous functionsMethod chainsRecursionDivide and conquerLazy evaluation
CallbacksArray.prototype.map()Array.prototype.filter()Array.prototype.reduce()Honorable mentionsArray.prototype.forEachArray.prototype.concatArray.prototype.reverseArray.prototype.sortArray.prototype.every and Array.prototype.some
Introduction
Underscore.jsFantasy LandBilby.jsLazy.jsBacon.jsHonorable mentions
BrowsersServer-side JavaScriptA functional use case in the server-side environmentCLIUsing functional libraries with other JavaScript modulesFunctional languages that compile into JavaScript
Partial function application and curryingFunction manipulationApply, call, and the this keywordBinding argumentsFunction factoriesPartial applicationPartial application from the leftPartial application from the rightCurrying
ComposeSequence – compose in reverseCompositions versus chainsProgramming with compose
Handling events
ReactivityPutting it all together
Category theoryCategory theory in a nutshellType safetyObject identities
Creating functorsArrays and functorsFunction compositions, revisited
MaybesPromisesLensesjQuery is a monad
RecursionTail recursionThe Tail-call eliminationTrampoliningThe Y-combinatorMemoization
Scope resolutionsGlobal scopeLocal scopeObject propertiesClosuresGotchas
Function declarationsFunction expressionsThe function constructorUnpredictable behavior
JavaScript – the multi-paradigm language
InheritanceJavaScript's prototype chainInheritance in JavaScript and the Object.create() method
Functional inheritanceStrategy PatternMixinsClassical mixinsFunctional mixins

Content preview from JavaScript: Functional Programming for JavaScript Developers

Interacting with the user interface

A great deal of the JavaScript in use today is used on the client and is used to interact with elements that are visible on the screen. Interacting with the page flows through a model of the page known as Document Object Model (DOM).

Every element on the page is represented in the DOM. Whenever a change is made to the page, the DOM is updated. If we add a paragraph to the page, then a paragraph is added to the DOM. Thus if our JavaScript code adds a paragraph, checking that it does so is simply a function of checking the DOM.

Unfortunately, this requires that a DOM actually exists and that it is formed in the same way that it is on the actual page. There are a number of approaches to testing against a page.