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Testable JavaScript

Cover of Testable JavaScript by Mark Ethan Trostler Published by O'Reilly Media, Inc.
  1. Testable JavaScript
  2. Dedication
  3. Preface
    1. The Goal of This Book
    2. Who This Book Is For
    3. Who This Book Is Not For
    4. Who I Am
    5. What You Will Learn from This Book
      1. Content
    6. If You Like (or Don’t Like) This Book
    7. Recap
    8. How to Contact Us
    9. Conventions Used in This Book
    10. Using Code Examples
    11. Safari® Books Online
    12. Thanks!
  4. 1. Testable JavaScript
    1. Prior Art
      1. Agile Development
      2. Test-Driven Development
      3. Behavior-Driven Development
      4. The Best Approach?
    2. Code Is for People
      1. Why
      2. What
      3. How
    3. Beyond Application Code
      1. Testing
      2. Debugging
    4. Recap
  5. 2. Complexity
    1. Code Size
    2. JSLint
    3. Cyclomatic Complexity
    4. Reuse
    5. Fan-Out
    6. Fan-In
    7. Coupling
      1. Content Coupling
      2. Common Coupling
      3. Control Coupling
      4. Stamp Coupling
      5. Data Coupling
      6. No Coupling
      7. Instantiation
    8. Coupling Metrics
    9. Coupling in the Real World
      1. Testing Coupled Code
    10. Dependency Injection
    11. Comments
      1. YUIDoc
      2. JSDoc
      3. Docco/Rocco
    12. The Human Test
    13. Recap
  6. 3. Event-Based Architectures
    1. The Benefits of Event-Based Programming
    2. The Event Hub
      1. Using the Event Hub
      2. Responses to Thrown Events
      3. Event-Based Architectures and MVC Approaches
      4. Event-Based Architectures and Object-Oriented Programming
      5. Event-Based Architectures and Software as a Service
    3. Web-Based Applications
    4. Testing Event-Based Architectures
    5. Caveats to Event-Based Architectures
      1. Scalability
      2. Broadcasting
      3. Runtime Checking
      4. Security
      5. State
    6. A Smarter Hub: The Event Switch
      1. Deployment
      2. An Implementation
      3. Sessions
      4. Extensibility
    7. Recap
  7. 4. Unit Tests
    1. A Framework
    2. Let’s Get Clean
    3. Writing Good Tests
      1. Isolation
      2. Scope
      3. Defining Your Functions
      4. Positive Testing
      5. Negative Testing
      6. Code Coverage
    4. Real-World Testing
      1. Dependencies
      2. Asynchronous Testing
    5. Running Tests: Client-Side JavaScript
      1. PhantomJS
      2. Selenium
    6. Running Tests: Server-Side JavaScript
      1. Jasmine
    7. Recap
  8. 5. Code Coverage
    1. Coverage Basics
    2. Code Coverage Data
    3. A Hands-on Example
      1. Instrumenting Files
      2. Anatomy of a Coveraged File
    4. Exercise/Deploy
      1. Client-Side JavaScript
      2. Server-Side JavaScript
    5. Persisting Coverage Information
      1. Unit Tests
      2. Integration Tests
    6. Generating Output
    7. Aggregation
    8. Hidden Files
    9. Coverage Goals
    10. Recap
  9. 6. Integration, Performance, and Load Testing
    1. Integration Testing
      1. Selenium
      2. CasperJS
    2. Performance Testing
      1. Generating HAR Files
      2. Viewing HAR Files
      3. Browser Performance Testing
    3. Load Testing
      1. Browser Load Testing
    4. Tracking Resource Usage
      1. Client-Side Tracking
      2. Server-Side Tracking
    5. Recap
  10. 7. Debugging
    1. In-Browser Debugging
      1. Firefox
      2. Chrome
      3. Safari
      4. Internet Explorer
    2. Node.js Debugging
    3. Remote Debugging
      1. Chrome
      2. PhantomJS
      3. Firefox
    4. Mobile Debugging
      1. Android 4
      2. iOS 6
      3. Adobe Edge Inspect
      4. Other Mobile Debugging Options
    5. Production Debugging
      1. Minified Code
      2. Source Maps
    6. Recap
  11. 8. Automation
    1. What to Automate
    2. When to Automate
    3. How to Automate
      1. Automating with Continuous Integration
      2. Automating the Development Environment
      3. Automating the Build Environment
      4. Deployment
    4. Recap
  12. Index
  13. About the Author
  14. Colophon
  15. Copyright
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Chapter 7. Debugging

Debugging sucks. I heartily recommend not doing it. For those rare times when you must, however, there are many great tools and techniques to assist you.

In-Browser Debugging

Debugging client-side JavaScript invariably leads to using the debuggers provided by the various browsers themselves, or extensions to the browsers. You can view the current market share of each browser worldwide, or in your region, at the StateCounter website. Figure 7-1 shows the graph as of October 2012.

Of course, your web server logs will provide the most accurate assessment of browser usage for your application, but according to the global statistics shown in Figure 7-1, usage of Google Chrome is on the rise while all other browsers are either declining or stagnant. In terms of specific browser versions, Figure 7-2 shows that as of October 2012, use of Chrome 17 and IE 9.0 was rising, while use of all other major browser versions, representing only about a 15% share of the market, was falling. The scariest part of the graph in Figure 7-2 is the dotted line. This line represents mobile and tablet browsers, and its position in the graph indicates that these browsers are used more than the others.

We will discuss debugging on mobile and tablet browsers later in the chapter. In the meantime, let’s take a quick look at the various debuggers each major desktop browser provides. I will highlight some basics and differences between them, but for the most part they are similar and are constantly ...

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