Slots

The property system: declaration, slot annotations, runtime type checks, lifecycle hooks, and metadata consumers.

Overview

Slots are Strvct's property system. In traditional JavaScript objects, instance fields are simple key-value pairs without metadata. In Strvct, declaring a property as a slot transforms it into a rich metadata carrier that each framework layer reads independently.

Declaration Syntax & Slot Maps

Slots are declared inside initPrototypeSlots() during class registration. Declaring a slot installs a private variable (_slotName), an auto-generated getter (slotName()), and an auto-generated setter (setSlotName(value)) on the class prototype.

Each class prototype maintains two slot maps:

slotsMap(): Map of slots defined directly on this specific class.
allSlotsMap(): Map of all slots from this class and every ancestor class, accumulated down the prototype chain.

(class Character extends SvStorableNode {

    initPrototypeSlots () {
        {
            const slot = this.newSlot("name", "");
            slot.setSlotType("String");
            slot.setShouldStoreSlot(true);   // Included in IndexedDB record rows
            slot.setSyncsToView(true);       // Posts didChangeSlot notification
            slot.setCanEditInspection(true); // Editable field in Property Inspector
        }
        {
            const slot = this.newSlot("ownerNode", null);
            slot.setIsWeak(true);            // WeakRef memory safety
            slot.setSyncsToView(true);
        }
    }

}.initThisClass());

Complete Annotation Setters Table

Setter Method	Default	Purpose / Subsystem Consumer
`setSlotType("String")`	`"Object"`	Controls type validation, form field input type, and LLM JSON schema generation.
`setIsWeak(true)`	`false`	Holds value via `WeakRef` to prevent retain cycles in parent/owner back references.
`setIsLazy(true)`	`false`	Defers initialization or loading until the first getter call.
`setShouldStoreSlot(true)`	`false`	Instructs `SvObjectPool` to include property in serialized IndexedDB record rows.
`setIsInCloudRecord(true)`	`true`	When set to `false`, retains property in local IndexedDB but strips it from cloud commits.
`setSyncsToView(true)`	`false`	Emits `"didChangeSlot"` notification via `SvNotificationCenter` upon mutation.
`setCanEditInspection(true)`	`false`	Exposes field for direct editing in the modifier-click (Option+Click) Property Inspector.
`setIsSubnode(true)`	`null`	Adds slot value automatically to parent's `subnodes` array during `finalInit()`.
`setIsSubnodeField(true)`	`null`	Generates a navigable field tile (`SvField`) in the UI inspector hierarchy.
`setFinalInitProto(ClassName)`	`null`	Auto-instantiates default child objects during `finalInit()` if absent from storage.
`setIsBlobString(true)`	`false`	Long text slot whose payload spills to a SHA-256 text blob in storage.
`setIsPromiseWrapped(true)`	`false`	Auto-wraps getter return values in a Promise for async interface operations.
`setDuplicateOp("duplicate")`	`"nop"`	Cloning policy when duplicating nodes (`"nop"`, `"copyValue"`, `"duplicate"`).
`setValidValues([a, b])`	`null`	Restricts values to an allowed set, rendering dropdown options in the UI.
`setAllowsNullValue(true)`	`false`	Relaxes runtime validation to permit `null` slot values.
`setTranslationContext("ui")`	`null`	Declares i18n category for auto-translating string values.

Slot Constructor Variants

newSlot(name, defaultValue): Standard slot constructor with auto getter and setter.
newWeakSlot(name, defaultValue): Creates a slot holding a WeakRef. The getter unwraps the weak reference automatically; the setter wraps new values in WeakRef. Prevents retain cycles in parent-child back references.
newSubnodeFieldSlot(name, Class): Convenience constructor for navigable subnode field properties.
overrideSlot(name, defaultValue): Overrides a slot inherited from a superclass, preserving metadata while changing the default value.

Slot Change & Getter Hooks

Auto-generated getters and setters execute optional lifecycle hooks on the owning object if defined:

(class Character extends SvStorableNode {

    initPrototypeSlots () {
        {
            const slot = this.newSlot("inventory", null);
            slot.setSlotType("Inventory");
        }
    }

    // Optional lazy initialization hook called BEFORE getter returns value
    willGetSlotInventory () {
        if (!this._inventory) {
            this.setInventory(Inventory.clone());
        }
    }

    // Optional hook called BEFORE setter updates value
    willUpdateSlotInventory (oldVal, newVal) {
        console.log("Inventory changing from", oldVal, "to", newVal);
    }

    // Optional hook called AFTER setter updates value
    didUpdateSlotInventory (oldVal, newVal) {
        this.recalculateTotalWeight();
    }

}.initThisClass());

Runtime Type Checking

Auto-generated setters enforce runtime type checks against setSlotType(). When a type mismatch occurs (e.g. attempting to pass a string to a Number slot), the setter logs a warning and attempts safe type coercion (e.g. Number("12")), protecting object graph state from corrupt data.

Nodes: Core SvNode domain abstraction.
Implementation Overview: Deep dive into slot specs and class lifecycles.
Slot Change Hooks: Declarative setter hooks.