Replay AI: The Ultimate Solution for Migrating Legacy UI to React from Video

TL;DR: Replay AI revolutionizes legacy UI migration to React by analyzing video recordings of existing interfaces, generating clean, functional code that understands user behavior, not just visual layouts.

Migrating legacy UI to modern React frameworks is a notorious bottleneck. The process is often manual, error-prone, and time-consuming. Traditional approaches, like screenshot-to-code tools, fall short because they lack context: they only "see" the static visual representation, not the dynamic user interactions and underlying logic. This leads to brittle code that requires extensive rework.

Enter Replay, the video-to-code engine powered by Gemini. Replay analyzes video recordings of your legacy UI, understanding user behavior and intent. This "Behavior-Driven Reconstruction" approach ensures that the generated React code not only looks right but also behaves right, mirroring the functionality of the original system.

The Problem with Traditional UI Migration#

The typical UI migration workflow looks something like this:

1. •Manual Analysis: Developers painstakingly analyze the existing UI, often relying on outdated documentation or tribal knowledge.
2. •Screenshot-to-Code (Maybe): Attempting to use screenshot-to-code tools, which generate basic UI elements but lack functional understanding.
3. •Code Generation: Writing React components from scratch, a slow and error-prone process.
4. •Integration & Testing: Integrating the new components into the existing system and conducting extensive testing to ensure functionality.

This process is slow, expensive, and often results in code that doesn't accurately reflect the original UI's behavior. Screenshot-to-code tools, while helpful for basic layouts, fail to capture the nuances of user interaction. They generate static representations, leaving developers to manually implement the dynamic logic.

Replay: Behavior-Driven Reconstruction#

Replay takes a fundamentally different approach. Instead of relying on static screenshots or manual analysis, Replay analyzes video recordings of users interacting with the legacy UI. This allows Replay to understand:

• •User Flows: How users navigate through the application.
• •Data Input: What data users enter and how it affects the UI.
• •Dynamic Behavior: How the UI responds to user actions.

This understanding is then used to generate clean, functional React code that accurately reflects the behavior of the original UI. Replay's "Behavior-Driven Reconstruction" approach ensures that the generated code is not only visually accurate but also functionally equivalent to the legacy system.

Key Features of Replay#

Replay offers a range of features designed to streamline the UI migration process:

• •Multi-Page Generation: Replay can generate code for entire multi-page applications, capturing complex user flows.
• •Supabase Integration: Seamlessly integrate with Supabase for backend data management.
• •Style Injection: Automatically inject styles to match the look and feel of the original UI.
• •Product Flow Maps: Visualize user flows and identify potential areas for optimization.

💡 Pro Tip: Record multiple users interacting with the same UI to capture a wider range of behaviors and edge cases. This will improve the accuracy and robustness of the generated code.

Migrating Legacy UI with Replay: A Step-by-Step Guide#

Here's how you can use Replay to migrate your legacy UI to React:

Step 1: Record the UI#

Record videos of users interacting with the legacy UI. Focus on capturing a variety of user flows and edge cases. Ensure clear and consistent video quality for optimal analysis.

Step 2: Upload to Replay#

Upload the video recordings to Replay. Replay will automatically analyze the video and generate React code.

Step 3: Review and Refine#

Review the generated code and make any necessary refinements. Replay provides tools for editing and customizing the generated code.

Step 4: Integrate and Test#

Integrate the generated React components into your existing system and conduct thorough testing to ensure functionality.

Example: Generating a React Form with Replay#

Let's say you have a legacy HTML form that you want to migrate to React. Here's the legacy HTML:

html
<form>
  <label for="name">Name:</label><br>
  <input type="text" id="name" name="name"><br>
  <label for="email">Email:</label><br>
  <input type="email" id="email" name="email"><br><br>
  <input type="submit" value="Submit">
</form>

Instead of manually rewriting this in React, you record a video of someone filling out the form. Replay analyzes the video and generates the following React code (example):

typescript
import React, { useState } from 'react';

const LegacyForm = () => {
  const [name, setName] = useState('');
  const [email, setEmail] = useState('');

  const handleSubmit = (event: React.FormEvent) => {
    event.preventDefault();
    console.log('Name:', name);
    console.log('Email:', email);
    // Submit logic here
  };

  return (
    <form onSubmit={handleSubmit}>
      <label htmlFor="name">Name:</label><br />
      <input
        type="text"
        id="name"
        name="name"
        value={name}
        onChange={(e) => setName(e.target.value)}
      /><br />
      <label htmlFor="email">Email:</label><br />
      <input
        type="email"
        id="email"
        name="email"
        value={email}
        onChange={(e) => setEmail(e.target.value)}
      /><br /><br />
      <input type="submit" value="Submit" />
    </form>
  );
};

export default LegacyForm;

This generated code not only replicates the visual structure of the original form but also includes the necessary state management and event handling for a functional React component. Replay understands that the text fields are intended for user input and correctly implements the

handlers.

⚠️ Warning: While Replay significantly reduces manual coding, always review and test the generated code to ensure accuracy and address any edge cases not captured in the video recordings.

Benefits of Using Replay#

• •Reduced Development Time: Automate the UI migration process and significantly reduce development time.
• •Improved Accuracy: Ensure that the generated code accurately reflects the behavior of the original UI.
• •Reduced Errors: Minimize the risk of errors associated with manual code conversion.
• •Enhanced Collaboration: Facilitate collaboration between developers and designers by providing a common platform for UI migration.
• •Maintain Legacy Functionality: Accurately translate legacy functionality into modern React components.

📝 Note: Replay is particularly useful for migrating complex UIs with intricate user flows. The more complex the UI, the greater the time savings and accuracy improvements you'll see with Replay.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features and usage. Paid plans are available for more advanced features and higher usage limits.

How is Replay different from v0.dev?#

While both Replay and v0.dev aim to generate code, they operate on different principles. v0.dev primarily uses AI to generate UI based on text prompts, whereas Replay uses video analysis to reconstruct existing UI with a focus on behavior and functionality. Replay is ideal for migrating existing UIs, while v0.dev is better suited for creating new UIs from scratch. Replay focuses on accurately replicating existing functionality, while v0.dev prioritizes creative UI generation.

What types of videos work best with Replay?#

Videos with clear visuals, consistent lighting, and minimal background noise work best. Ensure the video captures all relevant user interactions and edge cases.

What frameworks are supported?#

Currently, Replay primarily supports React. Future versions may include support for other popular frameworks.

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