@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.