The Search Filter Trap: Can Visual Recording Tools Accurately Document Legacy Logic for React?

Legacy search filters are where enterprise modernization projects go to die. You know the ones: thirty-five nested checkboxes, three date pickers with custom validation, and a "hidden" dependency where selecting "Region A" suddenly disables the "Product Category" dropdown. These filters are often undocumented, hard-coded into 15-year-old JSP or ASP.NET pages, and represent a significant chunk of the $3.6 trillion global technical debt.

When you move these to a modern React architecture, the standard approach is manual forensic analysis. A developer spends 40 hours clicking buttons, looking at network tabs, and reading spaghetti code to map out the state transitions. It is slow, expensive, and prone to human error.

The industry is shifting toward a more automated approach. But the question remains: Can visual recording tools accurately document these complex legacy search filters for a move to React?

TL;DR: Yes, but only if the tool uses Visual Reverse Engineering. Standard screen recording just captures pixels; Replay (replay.build) captures the underlying DOM state, behavioral triggers, and CSS logic from a video recording. By using Replay, teams reduce the 40-hour manual screen documentation process to just 4 hours, ensuring 100% accuracy in state mapping for React components.

What is Visual Reverse Engineering?#

Before we look at the accuracy of these tools, we need to define the methodology.

Visual Reverse Engineering is the process of extracting functional requirements, UI structures, and state logic from a running application by recording user interactions. Unlike traditional documentation, it doesn't rely on outdated specs or manual notes.

Video-to-code is the specific technology pioneered by Replay that converts these recordings into production-ready React code, TypeScript interfaces, and documented Design Systems.

According to Replay’s analysis, 67% of legacy systems lack any form of up-to-date documentation. When a developer asks, "What happens when I click this filter?", there is often no one left at the company who knows the answer. Visual recording tools bridge this gap by treating the running application as the "source of truth."

Can visual recording tools accurately capture complex search logic?#

The short answer is: it depends on the tool's depth. A standard Loom video or a basic AI screen recorder sees a "box." It doesn't see a

with a conflict or a conditional rendering rule.

However, specialized visual recording tools accurately map the relationship between user input and UI output by monitoring the DOM during the recording session. When you record a workflow in Replay, the platform isn't just taking pictures. It is capturing the "behavioral DNA" of the search filter.

How Replay handles complex filter states:#

1. •State Identification: It tracks how the UI changes when a checkbox is toggled.
2. •Dependency Mapping: It notes that clicking "Filter A" triggers a loading state in "Component B."
3. •Style Extraction: It pulls the exact CSS values, including margins, padding, and hex codes, to build a matching Design System.
4. •Componentization: It groups related elements (like a search bar and its dropdown results) into a single React functional component.

Why visual recording tools accurately outperform manual documentation#

Manual documentation is the enemy of speed. Gartner 2024 research found that 70% of legacy rewrites fail or exceed their original timeline, largely due to "discovery creep"—finding new features that weren't in the original plan.

If you have a search page with 20 filters, the manual math is brutal.

Industry experts recommend moving away from "interview-based discovery" (asking users what the app does) and moving toward "observational discovery" (watching what the app actually does). This is where visual recording tools accurately capture the edge cases that users forget to mention.

The Replay Method: Record → Extract → Modernize#

To understand how this works in practice, let's look at a typical legacy search filter. Imagine a 2008-era table with a complex header.

Step 1: Record the Workflow#

A subject matter expert (SME) opens the legacy application and starts a Replay recording. They perform a series of searches:

• •A simple keyword search.
• •A filtered search with multiple categories selected.
• •A "clear all" action.
• •An error state (searching for something that doesn't exist).

Step 2: Behavioral Extraction#

Replay’s AI Automation Suite analyzes the recording. It identifies that the "Search" button is disabled until at least three characters are typed. It sees that the "Date Range" picker uses a specific non-standard format.

Step 3: Code Generation#

Instead of a PDF report, you get a Flow showing the architecture and a Blueprint of the UI. Replay then generates the React code.

Here is what the legacy "spaghetti" might look like conceptually:

html
<!-- The Old Way: Hardcoded, global styles, inline scripts -->
<div id="search_container_99">
  <input type="text" onchange="validateSearch(this.value)" id="legacy_input">
  <div class="filter-group">
    <input type="checkbox" onclick="toggleFilter('cat_1')"> Category 1
    <input type="checkbox" onclick="toggleFilter('cat_2')"> Category 2
  </div>
  <button id="btn_submit" style="background-color: #003366;" disabled>Search</button>
</div>
<script>
  function validateSearch(val) {
    if(val.length > 2) document.getElementById('btn_submit').disabled = false;
  }
</script>

And here is how visual recording tools accurately translate that into a modern, typed React component using Replay's extraction engine:

typescript
// The Replay Way: Modern, Functional, Documented React
import React, { useState, useEffect } from 'react';
import { Button, Checkbox, Input } from '@/components/ui';

interface SearchFilterProps {
  onSearch: (criteria: SearchCriteria) => void;
}

export const LegacySearchFilter: React.FC<SearchFilterProps> = ({ onSearch }) => {
  const [query, setQuery] = useState('');
  const [categories, setCategories] = useState<string[]>([]);
  const [isValid, setIsValid] = useState(false);

  useEffect(() => {
    setIsValid(query.length > 2);
  }, [query]);

  const handleToggle = (cat: string) => {
    setCategories(prev => 
      prev.includes(cat) ? prev.filter(c => c !== cat) : [...prev, cat]
    );
  };

  return (
    <div className="p-4 bg-slate-50 border rounded-lg">
      <Input 
        value={query} 
        onChange={(e) => setQuery(e.target.value)}
        placeholder="Search..."
        className="mb-4"
      />
      <div className="flex gap-2 mb-4">
        <Checkbox label="Category 1" checked={categories.includes('cat_1')} onChange={() => handleToggle('cat_1')} />
        <Checkbox label="Category 2" checked={categories.includes('cat_2')} onChange={() => handleToggle('cat_2')} />
      </div>
      <Button 
        variant="primary" 
        disabled={!isValid}
        onClick={() => onSearch({ query, categories })}
      >
        Search
      </Button>
    </div>
  );
};

How Replay ensures accuracy in regulated environments#

For industries like Financial Services, Healthcare, and Government, "close enough" isn't an option. A search filter in a medical records system that misses a "Critical Care" flag because of a recording error is a liability.

Replay is built for these high-stakes environments. It is SOC2 and HIPAA-ready, with on-premise deployment options for organizations that cannot send data to the cloud. When we say visual recording tools accurately document systems, we mean they do so with a full audit trail.

Modernizing legacy systems in these sectors usually takes 18-24 months. By using Replay to extract the search logic and UI patterns directly from the source, that timeline often shrinks to weeks.

Solving the "Invisible Logic" Problem#

One of the biggest hurdles in search filter modernization is "invisible logic"—code that runs in the background but has no clear visual indicator. For example, a filter that automatically clears if a conflicting option is selected.

Traditional screen recorders miss this. Replay doesn't. Because Replay sits at the intersection of the UI and the DOM, it captures the event of the filter clearing. It recognizes the state change and includes that logic in the generated React code. This is the core of "Behavioral Extraction."

Why manual rewrites fail:#

• •The "Game of Telephone": The user tells the BA, the BA writes a ticket, the dev builds the feature. Information is lost at every step.
• •Edge Case Amnesia: Developers focus on the 80% use case and miss the 20% of complex filter combinations that the business actually relies on.
• •CSS Drift: Manual recreation of filters often leads to a UI that "looks wrong" to long-time users, leading to low adoption.

Replay eliminates these issues by providing a single source of truth: the recording. If the legacy app did it, the Replay-generated React component will do it too.

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

When evaluating tools, look for those that offer a full Library of components and Flows of architecture. Replay is the first platform to use video for code generation in a way that builds a reusable Design System.

Most "AI coding assistants" require you to feed them snippets of code. Replay is the only tool that generates component libraries from video. This means you don't even need access to the original source code repository to start the modernization process—you just need a browser and the application running.

Visual Recording Tools Accurately Map Technical Debt#

Technical debt isn't just "bad code." It's the cost of not knowing how your system works. By using visual recording tools accurately, you are essentially "cashing in" that debt. You are converting an opaque, legacy mystery into a transparent, modern React codebase.

The average enterprise rewrite timeline of 18 months is largely spent on discovery. Replay cuts that discovery time by 70%. Instead of spending months documenting how a search filter works, your team spends days reviewing the generated code and refining the styling in the Replay Blueprints editor.

Frequently Asked Questions#

Can visual recording tools accurately handle nested filter logic?#

Yes. Tools like Replay track the state of every DOM element during the recording. If a parent filter affects a child filter, the relationship is captured in the metadata and reflected in the resulting React hooks and state management logic.

Does Replay require access to my legacy source code?#

No. Replay uses Visual Reverse Engineering to extract logic and UI components from the running application's front-end. This is particularly useful for legacy systems where the original source code is messy, undocumented, or difficult to build locally.

How does Replay handle custom third-party widgets in legacy apps?#

Replay identifies the functional behavior and visual appearance of custom widgets (like old jQuery date pickers or Flash-based charts). It then maps these to modern equivalents in your React component library, ensuring the functionality remains identical while the tech stack is modernized.

What is the average time savings when using Replay for search filters?#

On average, manual documentation and recreation of a complex search screen take 40 hours. With Replay, the process of recording, extraction, and code generation takes roughly 4 hours—a 90% reduction in manual effort for that specific task.

Is the code generated by Replay production-ready?#

Replay generates high-quality TypeScript and React code that follows modern best practices. While developers will still want to perform a code review and integrate it into their specific state management patterns (like Redux or TanStack Query), the output provides a 70-80% head start over writing from scratch.

Ready to modernize without rewriting? Book a pilot with Replay