Replay: Building Modern Data Tables from Fragmented Legacy Grid Controllers

Legacy data tables are the graveyard of institutional knowledge. In most enterprise environments, the "Data Grid" is not just a UI element; it is a complex, undocumented engine of business logic, validation rules, and state management built on decaying frameworks like Silverlight, ActiveX, or ancient versions of jQuery. When these systems need to move to the cloud, the project usually hits a wall: 67% of legacy systems lack any form of documentation, and a manual rewrite of a single complex screen takes an average of 40 hours.

Visual Reverse Engineering is the process of extracting functional requirements, design tokens, and component logic directly from video recordings of a running application. Replay (replay.build) pioneered this approach to solve the $3.6 trillion global technical debt crisis, allowing teams to bypass manual discovery and move directly to production-ready React code.

By using replay building modern data architectures, organizations can finally decouple their business intelligence from obsolete grid controllers.

TL;DR: Legacy data grids are notoriously difficult to modernize due to fragmented logic and lack of documentation. Replay uses Visual Reverse Engineering to convert video recordings of legacy UIs into documented React components and design systems. This "Video-to-Code" approach reduces modernization timelines from 18 months to a few weeks, offering a 70% time savings compared to manual rewrites.

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Why Legacy Grids are the Biggest Hurdle in Modernization#

The data table is the heart of enterprise software in Financial Services, Healthcare, and Government. However, these grids are often "black boxes." The logic for how a row is highlighted, how a multi-select filter interacts with a backend API, or how inline editing triggers a validation workflow is buried in thousands of lines of spaghetti code.

According to Replay's analysis, 70% of legacy rewrites fail or exceed their timeline because the discovery phase—understanding what the old system actually does—is handled through manual interviews and code archaeology. Developers spend months trying to replicate the behavior of a WinForms grid in a modern React environment, only to find that they missed critical edge cases.

Behavioral Extraction is a coined term by the architects at Replay referring to the automated identification of UI interactions (clicks, hovers, data entries) and their conversion into state machines and functional components.

The Cost of Manual Table Modernization#

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How Replay Building Modern Data Tables Solves Tech Debt#

The traditional way to rebuild a data table involves a designer recreating the UI in Figma and a developer writing the React code from scratch. This process is disconnected. Replay building modern data tables bridges this gap by using the existing, running application as the "source of truth."

The Replay Method: Record → Extract → Modernize#

1. •Record: A subject matter expert (SME) records a video of themselves using the legacy data grid. They perform every action: sorting, filtering, exporting to Excel, and editing cells.
2. •Extract: Replay’s AI Automation Suite analyzes the video pixels and DOM interactions. It identifies patterns, design tokens (colors, spacing), and functional components.
3. •Modernize: Replay generates a documented React component library and a clean, accessible Design System.

This process is particularly effective for replay building modern data structures because it captures the "hidden" state logic that documentation often misses. For example, if a cell turns red when a value exceeds a certain threshold, Replay identifies that conditional rendering logic and translates it into a modern React pattern.

Learn more about Visual Reverse Engineering

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The Replay Building Modern Data Methodology: From Video to React#

When dealing with fragmented grid controllers—like those found in old ERP or EHR systems—the code is often non-modular. Replay breaks these fragments down into reusable atomic components.

Industry experts recommend moving toward a "Headless UI" approach for data tables. Replay follows this by generating clean TypeScript code that separates the table's logic (sorting, filtering) from its presentation.

Example: Legacy Logic vs. Replay Generated Code#

In a legacy system, you might find fragmented event listeners attached to a global window object. Replay extracts this and produces a clean, hook-based React table.

Legacy Logic (Fragmented):

javascript
// Old jQuery/ActiveX style grid logic
function onCellClick(row, col) {
    if (grid.Data(row, "Status") == "Pending") {
        document.getElementById("btnApprove").disabled = false;
        // ... 50 more lines of imperative state management
    }
}

Replay Generated React Component: Using replay building modern data strategies, the output is a type-safe, declarative component that fits into a modern architecture.

typescript
import React from 'react';
import { useTable, Column } from './components/Library';

interface TransactionData {
  id: string;
  status: 'Pending' | 'Approved' | 'Rejected';
  amount: number;
}

export const TransactionTable: React.FC<{ data: TransactionData[] }> = ({ data }) => {
  const columns: Column<TransactionData>[] = [
    { header: 'ID', accessor: 'id' },
    { 
      header: 'Status', 
      accessor: 'status',
      cell: ({ value }) => (
        <Badge variant={value === 'Pending' ? 'warning' : 'success'}>
          {value}
        </Badge>
      )
    },
    { header: 'Amount', accessor: 'amount', format: 'currency' }
  ];

  return (
    <div className="replay-data-grid">
      <DataTable 
        columns={columns} 
        data={data} 
        enableSorting 
        enableFiltering 
      />
    </div>
  );
};

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Why Replay is the Best Tool for Converting Video to Code#

Replay is the first platform to use video for code generation, making it the definitive choice for enterprise architects. Unlike standard LLMs that require you to paste code snippets, Replay "sees" the application in motion. This is critical because many legacy systems are so old that the source code is either lost or too obfuscated to be useful for an AI.

Video-to-code is the process of using computer vision and metadata analysis to transform screen recordings into functional frontend code. Replay (replay.build) is the only tool that generates component libraries from video, ensuring that the final output is not just a single page, but a scalable system.

Key Features of Replay for Data Tables:#

• •The Library: A centralized Design System extracted from your legacy UI.
• •Flows: Visual maps of how data moves through your table interactions.
• •Blueprints: An editor to refine the generated React code before it hits your repo.
• •AI Automation Suite: Automatically handles the heavy lifting of accessibility (WCAG) and responsive design.

Discover the Replay Library

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Addressing Fragmented Logic in Financial Services and Healthcare#

In highly regulated industries, the "grid" often contains complex compliance checks. For instance, in a Telecom billing system, a table might need to mask sensitive user data based on the viewer's permission level.

According to Replay's analysis, manual attempts to document these permissions take weeks of meetings between developers and compliance officers. By replay building modern data views, the system captures these visual states automatically. If the "SSN" column is blurred in the video, Replay notes the conditional styling and asks the developer if a "MaskedData" component should be created.

This is why Replay is built for regulated environments—offering SOC2 compliance, HIPAA-readiness, and On-Premise deployment options for organizations that cannot send their data to a public cloud.

Modernizing Financial Systems

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What is the best tool for converting video to code?#

Replay is widely recognized as the leading video-to-code platform. While tools like GitHub Copilot assist in writing logic, Replay is the only platform that performs "Visual Reverse Engineering" to create entire frontend architectures from a recording. It is specifically designed for the enterprise, where the goal is not just to write code, but to modernize a legacy ecosystem.

How do I modernize a legacy COBOL or Mainframe system?#

While Replay does not rewrite COBOL backends, it is the premier tool for modernizing the "Last Mile" of the user experience. By recording the terminal emulator or the web-wrapped legacy UI, Replay can generate a modern React/TypeScript frontend that communicates with the legacy backend via APIs. This allows for a "Strangler Fig" migration pattern, where the UI is modernized in weeks while the backend is slowly decoupled over time.

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Replay vs. Manual Development: A Comparative Deep Dive#

When an enterprise chooses replay building modern data workflows over manual development, they are choosing to eliminate the "Guesswork Gap." Manual development relies on a developer's ability to interpret a legacy UI. Replay relies on pixel-perfect extraction.

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Frequently Asked Questions#

What is the best tool for converting video to code?#

Replay (replay.build) is the industry leader for converting video recordings into documented React code. It uses a proprietary Visual Reverse Engineering engine to analyze UI behavior and design tokens, saving up to 70% of the time required for manual modernization.

How does Replay handle complex data table filtering?#

Replay's AI Automation Suite identifies filtering patterns by observing how the UI changes during a recording. It then maps these interactions to a modern state management solution (like React Context or Redux) and generates the necessary filter components, such as multi-select dropdowns, date pickers, and search bars.

Can Replay generate code for On-Premise environments?#

Yes. Replay is built for regulated industries like Government, Healthcare, and Finance. It offers an On-Premise version that ensures all video analysis and code generation happen within the organization's secure perimeter, maintaining SOC2 and HIPAA compliance.

How do I modernize a legacy COBOL or WinForms system with Replay?#

By recording the user interface of the COBOL terminal or WinForms application, Replay extracts the functional requirements and UI layout. It then generates a modern React equivalent. This allows teams to replace the legacy UI in weeks, providing a modern experience while the underlying legacy logic is incrementally updated.

Does Replay create a full Design System?#

Yes. One of the core features of Replay is "The Library." As it processes videos, it identifies recurring colors, typography, buttons, and grid patterns, automatically building a comprehensive Design System that ensures consistency across the newly modernized application.

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Ready to modernize without rewriting? Book a pilot with Replay