The Architecture of React Components Generated from Visual Workflows

The $3.6 trillion global technical debt isn't just a figure on a balance sheet; it is the graveyard of enterprise innovation. For the average CTO, legacy modernization is a high-stakes gamble where 70% of rewrites fail or exceed their timelines. The traditional "Big Bang" rewrite is an 18-to-24-month suicide mission that relies on "software archaeology"—the desperate attempt to understand undocumented codebases where the original authors left the company years ago.

The future of modernization isn't rewriting from scratch; it is understanding what you already have. By using visual reverse engineering, we can transform a legacy "black box" into a documented, modern codebase in days, not years.

TL;DR: The architecture of React components generated via visual workflows allows enterprises to bypass manual documentation and "Big Bang" risks, reducing modernization timelines by 70% through automated extraction of business logic and UI patterns directly from user sessions.

The Architecture of Visual Reverse Engineering#

When we discuss the architecture of modern React components, we are usually talking about Atomic Design or Feature-Based Folder structures. However, in the context of legacy modernization, the architecture begins with the Source of Truth. In a system where 67% of legacy code lacks documentation, the only reliable source of truth is the running application itself—the workflows that users execute every day.

Replay captures these workflows and translates them into a structured technical stack. This isn't "screen scraping." It is the systematic extraction of state transitions, API interactions, and UI hierarchies.

Comparison: Modernization Methodologies#

The Architecture of Generated React Components#

The output of a visual reverse engineering process must be more than just "working code." To be maintainable, the generated architecture must follow enterprise-grade patterns. When Replay processes a recorded workflow, it constructs a multi-layered React architecture designed for long-term ownership.

1. The Presentation Layer (The Library)#

Replay identifies recurring UI patterns across different legacy screens and consolidates them into a unified Design System. Instead of 50 different versions of a "Submit" button, the architecture generates a standardized component library.

2. The Logic Layer (The Blueprints)#

Business logic is often buried in 15-year-old stored procedures or spaghetti jQuery. Visual extraction maps the relationship between user input and system output. The resulting React components utilize custom hooks to isolate this logic, making it testable and independent of the UI.

3. The Data Layer (API Contracts)#

One of the greatest pain points in modernization is the "Black Box" API. Replay monitors the network traffic during the recording phase to generate precise API contracts (OpenAPI/Swagger) and TypeScript interfaces.

typescript
// Example: Generated component architecture from a Replay extraction
// This component preserves legacy business logic while using modern React patterns.

import React, { useState, useEffect } from 'react';
import { Button, Input, Alert } from '@/components/ui'; // From Replay Library
import { useLegacyValidation } from '@/hooks/useLegacyValidation'; // Extracted Logic
import { updateRecord } from '@/api/generatedService'; // Generated API Contract

interface LegacyScreenProps {
  recordId: string;
  initialData: Record<string, any>;
}

export const MigratedEnterpriseForm: React.FC<LegacyScreenProps> = ({ recordId, initialData }) => {
  const [formData, setFormData] = useState(initialData);
  const [status, setStatus] = useState<'idle' | 'saving' | 'error'>('idle');
  
  // Replay extracted this validation logic from the legacy workflow
  const { validate, errors } = useLegacyValidation('FINANCIAL_SERVICE_RULE_SET');

  const handleSubmit = async () => {
    if (!validate(formData)) return;
    
    setStatus('saving');
    try {
      await updateRecord(recordId, formData);
      setStatus('idle');
    } catch (e) {
      setStatus('error');
    }
  };

  return (
    <div className="p-6 space-y-4">
      <h2 className="text-xl font-bold">Account Modification</h2>
      {status === 'error' && <Alert type="error">Update failed. Check legacy logs.</Alert>}
      
      <Input 
        label="Account Balance"
        value={formData.balance}
        error={errors.balance}
        onChange={(val) => setFormData({...formData, balance: val})}
      />
      
      <Button 
        isLoading={status === 'saving'} 
        onClick={handleSubmit}
      >
        Synchronize Changes
      </Button>
    </div>
  );
};

💡 Pro Tip: When migrating regulated systems (Healthcare/Finance), ensure your extraction tool supports on-premise deployment to keep sensitive PII/PHI within your secure perimeter. Replay offers on-premise options for this exact reason.

The 4-Step Extraction Workflow#

Modernizing a screen manually takes an average of 40 hours when you account for discovery, CSS debugging, and logic replication. With Replay, this is compressed into a 4-hour cycle.

Step 1: Record the Source of Truth#

An analyst or subject matter expert (SME) performs the standard business process in the legacy application while Replay records the session. This captures the DOM mutations, network requests, and state changes.

Step 2: Visual Analysis and Mapping#

The AI Automation Suite analyzes the recording. It identifies:

• •Layout structures: Grids, tables, and forms.
• •State transitions: What happens when a button is clicked?
• •Data dependencies: Which API calls populate which fields?

Step 3: Component Synthesis (The Architecture of the UI)#

Replay generates React components using your preferred tech stack (e.g., Tailwind CSS, Shadcn/UI, or a custom Design System). It maps the legacy CSS to modern utility classes, removing 90% of the manual styling effort.

Step 4: Technical Debt Audit and Validation#

The system generates a Technical Debt Audit, highlighting areas where the legacy logic is redundant or where the API contract deviates from modern standards.

⚠️ Warning: Never trust a "black box" migration. Always validate generated API contracts against your backend logs to ensure edge cases (like 500 errors or timeouts) are handled in the new architecture.

Why The Architecture of Visual Workflows Wins#

The primary reason legacy migrations fail is the Information Gap. Developers are asked to build a system they don't understand, based on requirements that were written a decade ago.

Visual reverse engineering closes this gap by providing:

• •E2E Tests: Replay generates Playwright or Cypress tests based on the recorded video.
• •Documentation: The "Flows" feature provides a visual map of the application architecture.
• •Speed: 70% average time savings is the difference between a project being funded or being cancelled.

💰 ROI Insight: For a 50-screen enterprise application, manual modernization costs approximately $400,000 (at $100/hr). Using Replay, the cost drops to roughly $40,000, saving $360,000 and 1,800 man-hours.

Implementation: Generating API Contracts#

The architecture of a modernized system is only as strong as its data layer. Replay automatically generates TypeScript interfaces from your legacy traffic, ensuring your new React frontend is type-safe from day one.

typescript
/**
 * Generated by Replay AI Automation Suite
 * Legacy System: Insurance Claims Portal (v4.2)
 * Workflow: Claim Submission
 */

export interface ClaimPayload {
  claimId: string;
  policyNumber: string; // Extracted from Regex validation in legacy
  claimDate: string;    // ISO 8601 format
  claimAmount: number;
  attachments: Array<{
    fileName: string;
    fileType: 'PDF' | 'JPG' | 'PNG';
  }>;
}

export interface ClaimResponse {
  referenceNumber: string;
  estimatedProcessingTime: number; // minutes
  status: 'PENDING' | 'APPROVED' | 'REJECTED';
}

Frequently Asked Questions#

How long does legacy extraction take?#

While a manual rewrite of a complex enterprise screen takes 40+ hours, Replay reduces this to approximately 4 hours. A full module of 10-15 screens can typically be extracted and documented within a single work week.

What about business logic preservation?#

Replay doesn't just copy the UI; it records the functional outcomes of the logic. By observing how the system reacts to specific inputs, the AI generates "Blueprints" that replicate that logic in clean, modern TypeScript, which can then be verified against the legacy system's output.

Can Replay handle regulated environments?#

Yes. Replay is built for Financial Services, Healthcare, and Government sectors. It is SOC2 compliant, HIPAA-ready, and can be deployed entirely on-premise to ensure that no data ever leaves your secure environment during the reverse engineering process.

Does the generated code create new technical debt?#

No. Unlike "no-code" platforms that lock you into proprietary runtimes, Replay generates standard React, TypeScript, and CSS. The code is yours to own, edit, and maintain. It follows industry-standard architectural patterns like Atomic Design and Clean Architecture.

---

Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.