foldkit-mixins

Typed extension points for Foldkit views.

A component eventually gets used somewhere its author did not anticipate. One caller wants a brand treatment, another wants a tooltip, another wants analytics, another needs an ARIA attribute or a ResizeObserver. The usual answers are to keep adding props or to copy the component and edit its markup.

foldkit-mixins takes a different approach:

A view declares where it may be customized once. Callers attach appearance and element-level behavior to those named points later.

The view keeps its markup, state and Messages. The caller gets a typed customization surface instead of an open-ended bag of props.

Without a slot contract                 With a slot contract

Button                                  Button
├─ className                            ├─ root slot
├─ iconClassName                        ├─ icon slot
├─ tooltip                              └─ label slot
├─ tracking
├─ ariaLabelOverride                    callers attach independently:
├─ onFocusDecoration                    ├─ BrandStyle
└─ ...                                  ├─ TooltipBehavior
                                        └─ AnalyticsBehavior

This is not a second component system and it is not a state library. A slot ultimately resolves to ordinary Foldkit attributes.