Replay AI: Generating Accessible Components from Video using TDD principles

TL;DR: Replay leverages video analysis and AI to generate accessible UI components, adhering to Test-Driven Development (TDD) principles for robust and maintainable code.

The dirty little secret of AI-powered code generation is that most tools focus on visual similarity, not functional correctness. Screenshot-to-code is a dead end. You get pretty pictures, not working applications. We need to shift our focus from pixels to behavior. That's where Replay comes in.

From Video to Verifiable Code: A New Paradigm#

Traditional methods of UI development often involve a disconnect between design mockups and the final implemented product. This gap can lead to accessibility issues, inconsistent behavior, and a painful debugging process. Replay addresses this by using video as the source of truth, understanding user interactions and translating them into functional, accessible code.

Replay employs "Behavior-Driven Reconstruction," a process that analyzes video recordings of user interactions to infer the intended functionality and generate code that accurately reflects that behavior. This approach, combined with modern AI models like Gemini, allows for the creation of robust and accessible UI components that are inherently aligned with user needs.

Accessibility First: Building Inclusive Experiences#

Accessibility is often an afterthought in UI development. With Replay, accessibility is baked in from the start. By analyzing user interactions in video recordings, Replay can identify potential accessibility issues and generate code that adheres to accessibility best practices.

Here's how Replay helps create more accessible components:

• •Semantic HTML: Replay prioritizes semantic HTML elements (e.g.,
  text

  <article>
  ,
  text

  <nav>
  ,
  text

  <button>
  ) to ensure proper structure and meaning for screen readers and other assistive technologies.
• •ARIA Attributes: When necessary, Replay intelligently adds ARIA attributes to enhance accessibility for dynamic elements and complex interactions.
• •Keyboard Navigation: Replay analyzes user interactions to ensure that all interactive elements are navigable and operable using the keyboard.
• •Color Contrast: Replay considers color contrast ratios to ensure that text and other visual elements are easily readable for users with visual impairments.

Test-Driven Development (TDD) with Replay#

Replay not only generates code but also facilitates a Test-Driven Development (TDD) workflow. By understanding the intended behavior of a UI component from the video recording, Replay can generate initial test cases that verify that the generated code meets the specified requirements.

This approach offers several advantages:

• •Early Bug Detection: Tests are written before the code, forcing developers to think about potential edge cases and identify potential bugs early in the development process.
• •Improved Code Quality: TDD encourages the creation of modular, well-defined code that is easier to test and maintain.
• •Reduced Development Time: By catching bugs early, TDD can significantly reduce the time spent debugging and fixing issues later in the development cycle.

Step 1: Capture the User Flow#

Record a video of the desired user flow. This video serves as the single source of truth for Replay. Ensure the video clearly demonstrates all interactions and intended outcomes.

Step 2: Upload to Replay#

Upload the video to Replay. The AI engine will analyze the video, identify UI elements, and understand the intended behavior.

Step 3: Generate Code and Tests#

Replay generates the UI component code, along with corresponding test cases. The tests are designed to verify the functionality captured in the video.

Step 4: Refine and Iterate#

Review the generated code and tests. Refine the code as needed and add additional test cases to cover any edge cases or specific requirements.

Here's an example of a test case that Replay might generate for a simple button component:

typescript
// Example test case generated by Replay
import { render, screen, fireEvent } from '@testing-library/react';
import MyButton from './MyButton';

describe('MyButton', () => {
  it('should call the onClick handler when clicked', () => {
    const handleClick = jest.fn();
    render(<MyButton onClick={handleClick}>Click Me</MyButton>);
    const button = screen.getByText('Click Me');
    fireEvent.click(button);
    expect(handleClick).toHaveBeenCalledTimes(1);
  });

  it('should be accessible via keyboard', () => {
    render(<MyButton onClick={() => {}}>Click Me</MyButton>);
    const button = screen.getByText('Click Me');
    button.focus();
    expect(button).toHaveFocus();
  });
});

This example demonstrates how Replay can generate tests that verify the basic functionality of a button component, including its ability to handle click events and its accessibility via keyboard navigation.

Replay vs. the Competition#

The market is flooded with "AI" tools promising code generation. However, most rely on outdated approaches like screenshot analysis. Here's a comparison:

💡 Pro Tip: Leverage Replay's Supabase integration to instantly deploy generated code and integrate it into your existing CI/CD pipeline.

📝 Note: Replay doesn't just generate code; it generates contextually aware code that understands the user's intent.

Code Customization and Style Injection#

Replay generates clean, well-structured code that is easy to customize and extend. You can easily modify the generated code to meet your specific requirements, add new features, or integrate it with existing codebases.

Furthermore, Replay supports style injection, allowing you to apply custom styles to the generated UI components. This ensures that the components seamlessly integrate with your existing design system and maintain a consistent look and feel.

You can inject styles using CSS, Tailwind CSS, or any other styling framework. Replay automatically applies the styles to the generated components, ensuring that they are visually consistent with your application's overall design.

typescript
// Example of style injection using Tailwind CSS
const MyStyledButton = () => {
  return (
    <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-4 rounded">
      Click Me
    </button>
  );
};

⚠️ Warning: While Replay strives to generate accessible code, always manually review the generated code to ensure it meets your specific accessibility requirements.

Product Flow Maps: Visualizing User Journeys#

Replay goes beyond generating individual UI components. It can also generate product flow maps that visualize the user's journey through your application. By analyzing video recordings of user interactions, Replay can identify the different steps in a user flow and create a visual representation of the flow.

These product flow maps can be invaluable for understanding how users interact with your application and identifying potential areas for improvement. They can also be used to create more effective onboarding experiences and guide users through complex workflows.

Replay is not just another code generation tool. It's a paradigm shift in how we approach UI development, focusing on behavior, accessibility, and testability.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited usage. Paid plans are available for higher usage and additional features. Check Replay's pricing page for the most up-to-date information.

How is Replay different from v0.dev?#

v0.dev primarily uses text prompts to generate UI components. Replay, on the other hand, uses video analysis to understand user behavior and generate code that accurately reflects that behavior. This approach results in more accurate, accessible, and testable code. Furthermore, Replay supports multi-page application generation, a feature not available in v0.dev. Replay focuses on understanding the intent behind the UI, not just the visual representation.

What frameworks does Replay support?#

Replay currently supports React, with plans to expand support to other popular frameworks in the future.

Can I use Replay with my existing codebase?#

Yes, Replay generates clean, well-structured code that is easy to integrate with existing codebases.

---

Ready to try behavior-driven code generation? Get started with Replay - transform any video into working code in seconds.