“Headless” in React refers to a design pattern where UI components are separated into two parts:
  1. Logic/State Management - The “headless” part that handles all the business logic, state, and behavior
  2. UI/Presentation - The visual components that you style and customize

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How Headless Components Work

Headless components provide all the functionality without any default styling or visual elements. They give you:
  • Data processing
  • State management
  • Business logic
But leave the UI completely up to you.
The hardest parts of building complex UIs usually revolve around state, events, side-effects, data computation/management. By removing these concerns from the markup, styles and implementation details, our logic and components can be more modular and reusable.
— TanStack Quill Architecture