Elm in Action

Elm in Action
contents
preface
acknowledgments
about this book
Who should read this book
How this book is organized: a roadmap
About the code
liveBook discussion forum
Other online resources
about the author
about the cover illustration
Turkey/Ottoman Empire collection
brief contents
Part 1 Getting started
1 Welcome to Elm
1.1 How Elm fits in
1.2 Expressions
1.2.1 Using elm repl
1.2.2 Building expressions
1.2.3 Booleans and conditionals
1.3 Functions
1.3.1 Defining functions
1.3.2 Importing functions
1.3.3 Creating scope with let-expressions
1.3.4 Anonymous functions
1.3.5 Operators
1.4 Collections
1.4.1 Lists
1.4.2 Records
1.4.3 Tuples
Summary
2 Your first Elm application
2.1 Rendering a page
2.1.1 Describing a page using the Html module
2.1.2 Building a project
2.2 Handling user input with The Elm Architecture
2.2.1 Representing application state with a model
2.2.2 Handling events with messages and updates
Summary
3 Compiler as assistant
3.1 Documenting guarantees with type annotations
3.1.1 Adding optional type annotations
3.1.2 Annotating functions with type variables
3.1.3 Reusing annotations with type aliases
3.1.4 Annotating longer functions
3.2 Using case-expressions and custom types
3.2.1 Using case-expressions
3.2.2 Enumerating possibilities with custom types
3.2.3 Holding data in custom types
3.2.4 Representing flexible messages with custom types
3.3 Generating random numbers with commands
3.3.1 Describing random values with Random.Generator
3.3.2 Introducing commands to The Elm Architecture
3.3.3 Generating random values with Random.generate
Summary
Part 2 Production-grade Elm
4 Talking to servers
4.1 Preparing for server-loaded data
4.1.1 Modeling incremental initialization
4.1.2 Resolving data dependencies
4.2 Fetching data from a server
4.2.1 Describing HTTP requests
4.2.2 Sending HTTP requests
4.3 Decoding JSON
4.3.1 Decoding JSON strings into results
4.3.2 Decoding JSON collections
4.3.3 Decoding JSON HTTP responses
Summary
5 Talking to JavaScript
5.1 Using custom elements
5.1.1 Importing custom elements
5.1.2 Handling custom events
5.1.3 Responding to slider changes
5.2 Sending data to JavaScript
5.2.1 Creating a command by using a port
5.2.2 Receiving data from Elm
5.2.3 Timing DOM updates
5.3 Receiving data from JavaScript
5.3.1 Receiving real-time data from JavaScript via ports
5.3.2 Receiving initialization arguments via flags
Summary
6 Testing
6.1 Writing unit tests
6.1.1 Introducing tests
6.1.2 Unit testing a JSON decoder
6.1.3 Narrowing test scope
6.2 Writing fuzz tests
6.2.1 Converting unit tests to fuzz tests
6.2.2 Testing update functions
6.2.3 Creating multiple tests with one function
6.3 Testing views
6.3.1 Testing DOM structure
6.3.2 Fuzzing view tests
6.3.3 Testing user interactions
Summary
Part 3 Building bigger
7 Data modeling
7.1 Storing values by keys in dictionaries
7.1.1 Setting up the page
7.1.2 Storing photos by URL in a dictionary
7.2 Modeling trees by using recursive custom types
7.2.1 Defining trees by using custom types
7.2.2 Recursive messages
7.2.3 Event handlers with recursive messages
7.3 Decoding graphs and trees
7.3.1 Decoding dictionaries
7.3.2 Decoding recursive JSON
7.3.3 Accumulating while decoding
Summary
8 Single-page applications
8.1 Framing the page
8.1.1 Creating Main.elm
8.1.2 Rendering the header and footer
8.1.3 Skipping unnecessary renders with Html.Lazy
8.2 Routing
8.2.1 Handling the initial URL
8.2.2 Parsing URL paths
8.2.3 Handing URL changes
8.3 Delegating pages
8.3.1 Revising module structure
8.3.2 Initializing page states
8.3.3 Delegating page logic
Summary
appendix A Getting set up
A.1 Installing Node.js and NPM
A.2 Installing command-line tools
A.3 Obtaining the Elm in Action repository
A.4 Installing recommended optional tools
appendix B Installing Elm packages
B.1 Direct and indirect dependencies
B.2 Semantic versioning in packages
B.2.1 Semantic versioning enforced
B.2.2 Browsing package documentation
B.3 Example: Installing elm/url
appendix C Html.Lazy’s change check
C.1 lazy’s check for strings and numbers
C.2 lazy’s check for everything else
C.3 When memory locations stay the same
C.3.1 Memory locations for collections
C.3.2 Memory locations across updates
C.3.3 Memory locations for functions
C.3.4 Named top-level functions always keep the same memory location
index