@spectrum-web-components/core

Abstract base classes for Spectrum Web Components.

This package provides the behavior layer for 2nd-gen Spectrum Web Components and is not intended for direct external use. It is independent from 1st-gen — there is no runtime dependency between them.

For more information, visit the Spectrum Web Components repository.

Folder structure

The core package is private/internal, so we can organize foundational code for discoverability and incremental migration.

core/
  element/      # SpectrumElement, defineElement, and element infrastructure
  mixins/       # Reusable mixins (SizedMixin, ObserveSlotPresence, etc.)
  controllers/  # Reactive controllers (Lit controllers, observers, etc.)
  utils/        # Utility functions (DOM helpers, label extraction, etc.)
  components/   # Component base classes (already established)

Naming

All new folders and files in /core should be kebab-case.

Imports

Prefer the new top-level paths for new code:

• @spectrum-web-components/core/element
• @spectrum-web-components/core/mixins
• @spectrum-web-components/core/controllers
• @spectrum-web-components/core/utils

New code should use the top-level paths above.

Migration

See MIGRATION.md for guidance on where to place migrated code.