@sectile/core

Pure, renderer-neutral interaction semantics with explicit laws, failures, and resource bounds.

Scope

• Ordered structures: sequence, range, grid, and tree
• Reusable state: cursor, selection, expansion, revision, interaction gates, and finite collection windows
• Coordination primitives for generation-bound async work, nested layer stacks, and identity-based reordering
• Bounded geometry algebra, anchored placement calculations, and a generic metric index
• Composite behavior for selection, navigation, disclosure, editing, forms, and overlays
• UTF-16-safe text editing, exact decimal expressions, and dimension-checked units

Contract

Core modules contain no DOM, terminal, rendering, or styling behavior. Constructors validate their inputs and return typed Result values. Accepted transitions are deterministic and failure-atomic; policies make eligibility, boundaries, and ownership explicit.

Runtime APIs are exposed through focused package subpaths. The package root contains shared types and has no interaction authority.

Core geometry is value-level infrastructure. @sectile/virtual owns collection extents, viewport queries, dynamic measurement state, layout strategies, and virtual repair. DOM and other host adapters obtain actual platform measurements and pass that evidence across the boundary; Core never reads host elements.