Add partial rerendering to document sheets via a custom mixin

module/apps/GenericItemSheet.mjs

@@ -1,10 +1,15 @@
 import { __ID__, filePath } from "../consts.mjs";
+import { TAFDocumentSheetMixin } from "./mixins/TAFDocumentSheetMixin.mjs";
 
 const { HandlebarsApplicationMixin } = foundry.applications.api;
 const { ItemSheetV2 } = foundry.applications.sheets;
 const { setProperty } = foundry.utils;
 
-export class GenericItemSheet extends HandlebarsApplicationMixin(ItemSheetV2) {
+export class GenericItemSheet extends
+	TAFDocumentSheetMixin(
+	HandlebarsApplicationMixin(
+	ItemSheetV2,
+)) {
 	// #region Options
 	static DEFAULT_OPTIONS = {
 		classes: [
@@ -29,6 +34,17 @@ export class GenericItemSheet extends HandlebarsApplicationMixin(ItemSheetV2) {
 		header: { template: filePath(`templates/GenericItemSheet/header.hbs`) },
 		content: { template: filePath(`templates/GenericItemSheet/content.hbs`) },
 	};
+
+	/**
+	 * This tells the Application's TAFDocumentSheetMixin how to rerender this app
+	 * when specific properties get changed on the actor, so that it doesn't need
+	 * to full-app rendering if we can do a partial rerender instead.
+	 */
+	static PROPERTY_TO_PARTIAL = {
+		"name": [`header`],
+		"img": [`header`],
+		"system": [`content`],
+	};
 	// #endregion Options
 
 	// #region Instance Data

module/apps/PlayerSheet.mjs

@@ -2,24 +2,19 @@ import { __ID__, filePath } from "../consts.mjs";
 import { AttributeManager } from "./AttributeManager.mjs";
 import { attributeSorter } from "../utils/attributeSort.mjs";
 import { TAFDocumentSheetConfig } from "./TAFDocumentSheetConfig.mjs";
+import { TAFDocumentSheetMixin } from "./mixins/TAFDocumentSheetMixin.mjs";
 import { toPrecision } from "../utils/roundToPrecision.mjs";
 
 const { HandlebarsApplicationMixin } = foundry.applications.api;
 const { ActorSheetV2 } = foundry.applications.sheets;
-const { getProperty, hasProperty } = foundry.utils;
+const { getProperty } = foundry.utils;
 const { TextEditor } = foundry.applications.ux;
 
-const propertyToParts = {
+export class PlayerSheet extends
-	"name": [`header`],
+	TAFDocumentSheetMixin(
-	"img": [`header`],
+	HandlebarsApplicationMixin(
-	"system.attr": [`attributes`],
+	ActorSheetV2,
-	"system.attr.value": [`attributes`, `content`],
+)) {
-	"system.attr.max": [`attributes`, `content`],
-	"system.content": [`content`],
-	"system.carryCapacity": [`items`],
-};
-
-export class PlayerSheet extends HandlebarsApplicationMixin(ActorSheetV2) {
 
 	// #region Options
 	static DEFAULT_OPTIONS = {
@@ -59,6 +54,21 @@ export class PlayerSheet extends HandlebarsApplicationMixin(ActorSheetV2) {
 		},
 	};
 
+	/**
+	 * This tells the Application's TAFDocumentSheetMixin how to rerender this app
+	 * when specific properties get changed on the actor, so that it doesn't need
+	 * to full-app rendering if we can do a partial rerender instead.
+	 */
+	static PROPERTY_TO_PARTIAL = {
+		"name": [`header`],
+		"img": [`header`],
+		"system.attr": [`attributes`],
+		"system.attr.value": [`attributes`, `content`],
+		"system.attr.max": [`attributes`, `content`],
+		"system.content": [`content`],
+		"system.carryCapacity": [`items`],
+	};
+
 	static TABS = {
 		primary: {
 			initial: `content`,
@@ -67,7 +77,7 @@ export class PlayerSheet extends HandlebarsApplicationMixin(ActorSheetV2) {
 				{ id: `content` },
 				{ id: `items` },
 			],
-		}
+		},
 	};
 	// #endregion Options
 
@@ -136,21 +146,6 @@ export class PlayerSheet extends HandlebarsApplicationMixin(ActorSheetV2) {
 		return controls;
 	};
 
-	_configureRenderOptions(options) {
-		// Only rerender the parts of the app that got changed
-		if (options.renderContext === `updateActor`) {
-			const parts = new Set();
-			for (const property in propertyToParts) {
-				if (hasProperty(options.renderData, property)) {
-					propertyToParts[property].forEach(partID => parts.add(partID));
-				};
-			};
-			options.parts = options.parts?.filter(part => !parts.has(part)) ?? Array.from(parts);
-		};
-
-		super._configureRenderOptions(options);
-	};
-
 	async close() {
 		this.#attributeManager?.close();
 		this.#attributeManager = null;
@@ -250,7 +245,7 @@ export class PlayerSheet extends HandlebarsApplicationMixin(ActorSheetV2) {
 	};
 
 	async _prepareItem(item) {
-		const weightUnit = game.settings.get(__ID__, `weightUnit`)
+		const weightUnit = game.settings.get(__ID__, `weightUnit`);
 		const ctx = {
 			uuid: item.uuid,
 			img: item.img,

module/apps/mixins/TAFDocumentSheetMixin.mjs

@@ -0,0 +1,36 @@
+const { hasProperty } = foundry.utils;
+
+export function TAFDocumentSheetMixin(HandlebarsApplication) {
+	class TAFDocumentSheet extends HandlebarsApplication {
+		/** @type {Record<string, string[]> | null} */
+		static PROPERTY_TO_PARTIAL = null;
+
+		/**
+		 * This override is used by the mixin in order to allow for partial
+		 * re-rendering of applications based on what properties changed.
+		 * It requires that a static PROPERTY_TO_PARTIAL to be defined as
+		 * an object of path keys to arrays of part IDs in order to work.
+		 * This will not interfere with renders that are not started as
+		 * part of the actor update lifecycle.
+		 */
+		_configureRenderOptions(options) {
+
+			if (options.renderContext === `updateActor`) {
+				const propertyToParts = this.constructor.PROPERTY_TO_PARTIAL;
+				if (propertyToParts) {
+					const parts = new Set();
+					for (const property in propertyToParts) {
+						if (hasProperty(options.renderData, property)) {
+							propertyToParts[property].forEach(partID => parts.add(partID));
+						};
+					};
+					options.parts = options.parts?.filter(part => !parts.has(part)) ?? Array.from(parts);
+				}
+			};
+
+			super._configureRenderOptions(options);
+		};
+	};
+
+	return TAFDocumentSheet;
+};