Only rebuild when current panel changed (#5071)

* Only rebuild when current panel changed

* Oops

* Update yarn.lock

* copy dep to repo

* Update deep-equal.ts

* Comments

src/common/util/deep-equal.ts

@@ -0,0 +1,107 @@
+// From https://github.com/epoberezkin/fast-deep-equal
+// MIT License - Copyright (c) 2017 Evgeny Poberezkin
+export const deepEqual = (a: any, b: any): boolean => {
+  if (a === b) {
+    return true;
+  }
+
+  if (a && b && typeof a === "object" && typeof b === "object") {
+    if (a.constructor !== b.constructor) {
+      return false;
+    }
+
+    let i: number | [any, any];
+    let length: number;
+    if (Array.isArray(a)) {
+      length = a.length;
+      if (length !== b.length) {
+        return false;
+      }
+      for (i = length; i-- !== 0; ) {
+        if (!deepEqual(a[i], b[i])) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    if (a instanceof Map && b instanceof Map) {
+      if (a.size !== b.size) {
+        return false;
+      }
+      for (i of a.entries()) {
+        if (!b.has(i[0])) {
+          return false;
+        }
+      }
+      for (i of a.entries()) {
+        if (!deepEqual(i[1], b.get(i[0]))) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    if (a instanceof Set && b instanceof Set) {
+      if (a.size !== b.size) {
+        return false;
+      }
+      for (i of a.entries()) {
+        if (!b.has(i[0])) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    if (ArrayBuffer.isView(a) && ArrayBuffer.isView(b)) {
+      // @ts-ignore
+      length = a.length;
+      // @ts-ignore
+      if (length !== b.length) {
+        return false;
+      }
+      for (i = length; i-- !== 0; ) {
+        if (a[i] !== b[i]) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    if (a.constructor === RegExp) {
+      return a.source === b.source && a.flags === b.flags;
+    }
+    if (a.valueOf !== Object.prototype.valueOf) {
+      return a.valueOf() === b.valueOf();
+    }
+    if (a.toString !== Object.prototype.toString) {
+      return a.toString() === b.toString();
+    }
+
+    let keys: string[];
+    keys = Object.keys(a);
+    length = keys.length;
+    if (length !== Object.keys(b).length) {
+      return false;
+    }
+    for (i = length; i-- !== 0; ) {
+      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) {
+        return false;
+      }
+    }
+
+    for (i = length; i-- !== 0; ) {
+      const key = keys[i];
+
+      if (!deepEqual(a[key], b[key])) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  // true if both NaN, false otherwise
+  return a !== a && b !== b;
+};

src/layouts/partial-panel-resolver.ts

@@ -8,6 +8,7 @@ import {
   RouteOptions,
 } from "./hass-router-page";
 import { removeInitSkeleton } from "../util/init-skeleton";
+import { deepEqual } from "../common/util/deep-equal";
 
 const CACHE_URL_PATHS = ["lovelace", "developer-tools"];
 const COMPONENTS = {
@@ -80,7 +81,7 @@ const getRoutes = (panels: Panels): RouterOptions => {
 
 @customElement("partial-panel-resolver")
 class PartialPanelResolver extends HassRouterPage {
-  @property() public hass?: HomeAssistant;
+  @property() public hass!: HomeAssistant;
   @property() public narrow?: boolean;
 
   protected updated(changedProps: PropertyValues) {
@@ -92,11 +93,8 @@ class PartialPanelResolver extends HassRouterPage {
 
     const oldHass = changedProps.get("hass") as this["hass"];
 
-    if (
-      this.hass!.panels &&
-      (!oldHass || oldHass.panels !== this.hass!.panels)
-    ) {
-      this._updateRoutes();
+    if (this.hass.panels && (!oldHass || oldHass.panels !== this.hass.panels)) {
+      this._updateRoutes(oldHass?.panels);
     }
   }
 
@@ -109,7 +107,7 @@ class PartialPanelResolver extends HassRouterPage {
   }
 
   protected updatePageEl(el) {
-    const hass = this.hass!;
+    const hass = this.hass;
 
     if ("setProperties" in el) {
       // As long as we have Polymer panels
@@ -127,11 +125,20 @@ class PartialPanelResolver extends HassRouterPage {
     }
   }
 
-  private async _updateRoutes() {
-    this.routerOptions = getRoutes(this.hass!.panels);
-    await this.rebuild();
-    await this.pageRendered;
-    removeInitSkeleton();
+  private async _updateRoutes(oldPanels?: HomeAssistant["panels"]) {
+    this.routerOptions = getRoutes(this.hass.panels);
+
+    if (
+      !oldPanels ||
+      !deepEqual(
+        oldPanels[this._currentPage],
+        this.hass.panels[this._currentPage]
+      )
+    ) {
+      await this.rebuild();
+      await this.pageRendered;
+      removeInitSkeleton();
+    }
   }
 }