List of Listings

Chapter 1. Hello Dart

Listing 1.1. String interpolation in Dart

Listing 1.2. A simple class in Dart

Listing 1.3. Every class has an implicit interface

Listing 1.4. Factory constructors for default implementations

Listing 1.5. Libraries and source files

Listing 1.6. Functions as first-class objects

Listing 1.7. Interacting with the browser

Listing 1.8. Drawing on the browser canvas

Chapter 2. “Hello World” with Dart tools

Listing 2.1. HelloWorld.dart

Listing 2.2. HTML file that can run your Dart app in both Dart and JavaScript

Listing 2.3. HelloWorld.dart.js: output of dart2js

Listing 2.4. HelloWorld.html with status <div>

Listing 2.5. HelloWorld.dart: creating elements dynamically

Chapter 3. Building and testing your own Dart app

Listing 3.1. Adding a new Element to the document body

Listing 3.2. Building the PackList UI

Listing 3.3. PackList that reacts to user events

Listing 3.4. Basic class structure

Listing 3.5. Refactoring the addltem method to use your class

Listing 3.6. Adding a uiElement getter

Listing 3.7. Adding the isPacked property, getter, and setter

Listing 3.8. PackListTest.html: entry-point HTML file for your unit test

Listing 3.9. PackListTest.dart: client-side test suite boilerplate code

Listing 3.10. Testing for expectations in unit tests

Listing 3.11. Creating a custom PackList matcher

Chapter 4. Functional first-class functions and closures

Listing 4.1. Mixing concrete in Dart

Listing 4.2. Checking parameters passed by reference

Listing 4.3. Function that takes a function object as a parameter

Listing 4.4. Outer main() function uses the inner mix() function

Listing 4.5. Storing anonymous functions in a list

Listing 4.6. Recursive, typed, named function

Listing 4.7. Function type strongly types a function variable or parameter

Listing 4.8. Using typedef to declare a function signature

Listing 4.9. Creating a closure with a function as a return type

Chapter 5. Understanding libraries and privacy

Listing 5.1. loglib.dart functions and classes

Listing 5.2. packlist.dart importing the loglib.dart library

Listing 5.3. Generated JavaScript extract of the PackList app and loglib library

Listing 5.4. Adding logging method calls to the PackList application

Listing 5.5. packlist.dart using the Logger class imported from loglib

Listing 5.6. mixed_loglib.dart: library containing both public and private classes

Listing 5.7. loglib.dart with a private function

Listing 5.8. Complete functions.dart source file

Listing 5.9. Example pubspec.yaml for loglib

Listing 5.10. Library containing a main() method

Chapter 6. Constructing classes and interfaces

Listing 6.1. A simple User class

Listing 6.2. logon.dart: using an example AuthService

Listing 6.3. Using a mock authentication service

Listing 6.4. Defining an explicit interface

Listing 6.5. Implementing multiple interfaces

Listing 6.6. Using EnterpriseAuthService with multiple interfaces

Listing 6.7. logon_library.dart: getters, setters, and properties in interfaces

Listing 6.8. Using factory constructors for default implementations

Listing 6.9. Using a factory constructor to return an existing object from cache

Listing 6.10. Implementing a cache with static members

Listing 6.11. Creating a const constructor

Chapter 7. Extending classes and interfaces

Listing 7.1. A new User class

Listing 7.2. EnterpriseUser with additional functionality

Listing 7.3. EnterpriseUser overriding functionality from parent User class

Listing 7.4. logon.dart: overriding properties inherited from the parent class

Listing 7.5. Making User an abstract class

Listing 7.6. Calling toString() outputs a textual representation of the object

Listing 7.7. Overriding the toString() functionality from Object

Listing 7.8. Implementing noSuchMethod()

Chapter 8. Collections of richer classes

Listing 8.1. Permissions boilerplate code

Listing 8.2. Returning a list of AdminPermissions

Listing 8.3. Extracting the first two items from a collection using an iterator

Listing 8.4. Different ways to create a list

Listing 8.5. Creating and using a map of String and User

Listing 8.6. Using the dart:json library to convert between maps and strings

Listing 8.7. Using the Map putIfAbsent() method

Listing 8.8. User class that uses generic credentials

Listing 8.9. Using your generic User class in a type-safe manner

Listing 8.10. Ways to compare roles

Listing 8.11. Providing implementations of < and > with the operator keyword

Listing 8.12. Overloading the addition operator to add Roles to a User

Listing 8.13. Overloading the indexer operators

Listing 8.14. Letting a class implement Map so it can be converted to JSON

Chapter 9. Asynchronous programming with callbacks and futures

Listing 9.1. lottery_app.dart written in a synchronous, blocking style

Listing 9.2. lottery_app.dart: using callbacks

Listing 9.3. lottery.dart: adding a timer to getWinningNumber()

Listing 9.4. lottery_app.dart: introducing sequencing into an async callback

Listing 9.5. lottery_app.dart: using nested callbacks

Listing 9.6. lottery_app.dart using Future values and then() callbacks

Listing 9.7. lottery_app.dart: passing future values into a function

Listing 9.8. lottery_app.dart: chaining futures together to enforce ordering

Listing 9.9. lottery_app.dart: waiting for futures and chaining

Listing 9.10. lottery_app.dart: transforming a nonfuture value into a future value

Listing 9.11. lottery_test.dart: unit-testing getResultsString()

Listing 9.12. lottery_test.dart: testing async callback functions with expectAsync()

Listing 9.13. lottery_test.dart: testing multiple futures with wait() and expectAsync ()

Chapter 10. Building a Dart web app

Listing 10.1. DartExpense.html

Listing 10.2. DartExpense.dart main() function

Listing 10.3. Populating the content and actions <div>s with a view

Listing 10.4. ListView class, which builds the HTML table of expenses

Listing 10.5. getDynamicTable() to dynamically build an HTML table

Listing 10.6. Attaching an event handler to the Add button

Listing 10.7. Using the specific MouseEvent type to extract more event details

Chapter 11. Navigating offline data

Listing 11.1. Updated navigate() function that integrates with browser history

Listing 11.2. Updated main() function to listen for popState events

Listing 11.3. Utility function to extract a cookie value for a given cookie key

Listing 11.4. Changing the application’s first view if there’s a stateData cookie

Listing 11.5. Providing a toMap() method on the Expense and ExpenseType classes

Listing 11.6. Implementing the Map interface to support JSON.stringify()

Listing 11.7. fromMap() constructor: initializes an object from a map of properties

Listing 11.8. Adding/updating an expense in local storage

Listing 11.9. Reading the list of expenses out of local storage

Listing 11.10. Replacing mock data with real data

Chapter 12. Communicating with other systems and languages

Listing 12.1. app.dart: sendToJavaScript() function that calls postMessage()

Listing 12.2. ui_chart.dart: ChartView class that calls the JavaScript chart library

Listing 12.3. DartExpense.html: JavaScript to receive postMessage() data

Listing 12.4. Calling Chart library code from receiveFromDart()

Listing 12.5. JavaScript sendToDart() utility function

Listing 12.6. ui_chart.dart: receiving data from JavaScript into Dart

Listing 12.7. ui_edit.dart: converting from USD to GBP

Listing 12.8. ui_list.dart: enabling the View Chart button only if the app is online

Listing 12.9. ui_edit.dart

Listing 12.10. manifest.json: settings for creating an installable Chrome app

Chapter 13. Server interaction with files and HTTP

Listing 13.1. Accessing command-line options

Listing 13.2. Display the command-line options if none are provided

Listing 13.3. Implementing outputFile() with an InputStream

Listing 13.4. Serving simple HttpRequests from Dart

Listing 13.5. Serving static files

Listing 13.6. Updated main() function using all three handler classes

Listing 13.7. Implementing the FolderListHandler class

Listing 13.8. Sending data to the browser with FileContentHandler

Listing 13.9. The client-side part of the Dart File Browser application

Listing 13.10. Client HTML file hosting the client-side application

Chapter 14. Sending, syncing, and storing data

Listing 14.1. DartExpense.dart main() function creating a web socket connection

Listing 14.2. Adding connectToWebsocket() to the AppController class

Listing 14.3. Sending a client count when each browser connects

Listing 14.4. Adding onClosed() handler to the connection

Listing 14.5. Sending JSON data to the server with web sockets

Listing 14.6. Receiving and resending data from a web socket message

Listing 14.7. Receiving synchronization data in the browser

Listing 14.8. models.dart: Expense class updated to include a _rev JSON property

Listing 14.9. CouchDbHandler class’s _getStringFromInputStream() utility method

Listing 14.10. CouchDbHandler class’s _getData() utility method

Listing 14.11. CouchDbHandler: adding specific DartExpense functionality

Chapter 15. Concurrency with isolates

Listing 15.1. directoryAnalysis.dart

Listing 15.2. FileTypes isolate receiving data from the default isolate

Listing 15.3. Performing the file type and file size analyses in separate isolates

Listing 15.4. FileTypes and FileSizes isolates send results to the default isolate.

Listing 15.5. Closing a ReceivePort when all data is received

Listing 15.6. DirAnalysis.dart: reading the command-line arguments

Listing 15.7. DirAnalysis.dart: using spawnUri() to load a source file dynamically

Listing 15.8. Adding the receive handler to the isolate

Listing 15.9. batchDirAnalysis.dart: starting point for the batch application

Listing 15.10. Spawning worker isolates and passing initial data items

Listing 15.11. Implementing the default isolate receive() function

Appendix B. Defining classes and libraries

Listing B.1. my_library.dart

Listing B.2. source.dart

Listing B.3. other_library.dart

Listing B.4. other_library.dart with private elements