Function EntityRef

packages/core/src/ECS/Decorators/EntityRefDecorator.ts:57–119

()

 * ```
 */
export function EntityRef(): PropertyDecorator {
    return function (target: any, propertyKey: string | symbol) {
        const constructor = target.constructor;

        let metadata: EntityRefMetadata = constructor[ENTITY_REF_METADATA];
        if (!metadata) {
            metadata = {
                properties: new Set()
            };
            constructor[ENTITY_REF_METADATA] = metadata;
        }

        const propKeyString = typeof propertyKey === 'symbol' ? propertyKey.toString() : propertyKey;
        metadata.properties.add(propKeyString);

        Object.defineProperty(target, propertyKey, {
            get: function (this: Component) {
                const valueMap = getValueMap(this);
                return valueMap.get(propKeyString) || null;
            },
            set: function (this: Component, newValue: Entity | null) {
                const valueMap = getValueMap(this);
                const oldValue = valueMap.get(propKeyString) || null;

                if (oldValue === newValue) {
                    return;
                }

                const scene = this.entityId !== null ? getSceneByEntityId(this.entityId) : null;

                if (!scene || !scene.referenceTracker) {
                    valueMap.set(propKeyString, newValue);
                    return;
                }

                const tracker = scene.referenceTracker;

                if (oldValue) {
                    tracker.unregisterReference(oldValue, this, propKeyString);
                }

                if (newValue) {
                    if (newValue.scene !== scene) {
                        logger.error(`Cannot reference Entity from different Scene. Entity: ${newValue.name}, Scene: ${newValue.scene?.name || 'null'}`);
                        return;
                    }

                    if (newValue.isDestroyed) {
                        logger.warn(`Cannot reference destroyed Entity: ${newValue.name}`);
                        valueMap.set(propKeyString, null);
                        return;
                    }

                    tracker.registerReference(newValue, this, propKeyString);
                }

                valueMap.set(propKeyString, newValue);
            },