# Accordion
## 1. Definition
Accordion is a structured disclosure component that organizes content into expandable sections with strict behavioral constraints. It defines a deterministic interaction model based on selection rules. Each section is represented as an item with a trigger and content. The component ensures that state transitions are controlled and predictable. It eliminates ambiguity in open and closed states. The structure is enforced through composition. It operates as a declarative system rather than an imperative one. The behavior is encoded in data attributes. This ensures consistency across renders. It integrates directly with CanonRS primitives.
## 2. Core Contract
The core contract defines how items can be expanded or collapsed. Selection mode determines whether single or multiple items can be open. Collapsible behavior defines whether all items can close. Each item must contain a trigger and content. The contract ensures valid state transitions. Invalid states are prevented at compile-time. The DOM structure must follow the defined hierarchy. Behavior is driven by attributes, not events. This ensures deterministic execution.
## 3. Primitive Mapping
Accordion maps directly to AccordionPrimitive. Each sub-component corresponds to a primitive. AccordionItem maps to AccordionItemPrimitive. AccordionTrigger maps to AccordionTriggerPrimitive. AccordionContent maps to AccordionContentPrimitive. The mapping ensures consistency. UI components do not introduce additional logic. They act as pass-through adapters. This maintains a single source of truth.
## 4. State Model
State is managed through structured attributes. VisibilityState defines open and closed states. AccordionSelection controls allowed configurations. State transitions are deterministic. No hidden mutable state exists. The DOM reflects the current state. This ensures synchronization across environments. State is not managed externally.
## 5. Accessibility Model
Accessibility is enforced through primitives. ARIA roles are automatically applied. Each trigger is linked to its content. Screen readers can interpret state changes correctly. Keyboard navigation is supported. Focus behavior is consistent. No manual configuration is required.
## 6. SSR Guarantees
Accordion is SSR-safe by design. The initial state is rendered deterministically. Hydration does not introduce mismatches. The DOM structure remains consistent. No client-only logic is required. This ensures stable rendering across environments.
## 7. Composition Rules
Accordion enforces strict composition. Each item must contain required parts. Nested structures are supported. Invalid hierarchies are prevented. Components can be combined safely. This ensures predictable behavior.
## 8. Interaction Model
Interaction is driven by attribute changes. Triggers update visibility state. No imperative event handlers are required. State transitions are deterministic. The model prevents race conditions. It ensures consistent behavior.
## 9. Failure Modes Prevented
Accordion prevents invalid multi-open states. It avoids inconsistent state synchronization. It eliminates hydration mismatches. It prevents incorrect ARIA usage. It avoids manual state bugs. It ensures deterministic rendering.
## 10. CanonRS Guarantees
Accordion guarantees correctness through types. It enforces accessibility automatically. It ensures SSR safety. It provides deterministic behavior. It integrates with the CanonRS state engine. It eliminates invalid states. It ensures consistency across the system.