๐๏ธ The Scene: The Interview Kickoff
Interviewer: "We need a reusable table component for our enterprise platform. It must handle millions of rows, sustain 100+ updates per 10ms (HFT style), and be flexible enough for 50+ different engineering teams. How do you approach this?"
Interviewee: "To build a truly 5/5 system, we can't treat this as a UI widget. We have to treat it as a Data Orchestration Engine. I'll break this down into three layers:
The Headless Core: Logic-only layer for sorting, filtering, and grouping.
The High-Frequency Pipeline: Handling the 'Thundering Herd' of WebSocket updates.
The Rendering Layer: Using Virtualization and GPU-accelerated CSS."
๐ ๏ธ Phase 1: The API & Data Contract (MVP 0)
To ensure 50 teams can use this, we use a Headless Pattern. The table doesn't own the UI; it provides the state.
The Column Definition
TypeScript
๐ Phase 2: The "Thundering Herd" (Handling 100ms Updates)
Interviewer: "How do you handle 100 WebSocket messages in 10ms without the UI locking up?"
Interviewee: "We must decouple Ingestion from Rendering. If we call setState for every message, the React reconciler will crash. We use a RequestAnimationFrame (rAF) Buffer."
The Working Code: High-Frequency Update Manager
TypeScript
๐๏ธ Phase 3: System Design & Architecture
To scale, we move heavy computation (sorting 100k rows) off the main thread.
Code snippet
โก Phase 4: Extreme Performance Optimizations
1. Column Resizing via CSS Variables
Interviewer: "Resizing columns usually triggers a massive re-render. How do you avoid it?"
Interviewee: "I avoid React state for the resize movement. I define the table grid using CSS Variables. When the user drags, I update the variable on the parent container directly. The cells adjust via the browser's layout engine, bypassing React's diffing entirely."
TypeScript