upgrade lit (#2458)

* upgrade lit

* Lint

gallery/src/demos/demo-util-long-press.ts

@@ -1,12 +1,11 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 import "@polymer/paper-button/paper-button";
 
 import "../../../src/components/ha-card";
 import { longPress } from "../../../src/panels/lovelace/common/directives/long-press-directive";
 
 export class DemoUtilLongPress extends LitElement {
-  public render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       ${

package.json

@@ -17,7 +17,6 @@
   "author": "Paulus Schoutsen <Paulus@PaulusSchoutsen.nl> (http://paulusschoutsen.nl)",
   "license": "Apache-2.0",
   "dependencies": {
-    "@material/mwc-ripple": "^0.3.1",
     "@mdi/svg": "^3.0.39",
     "@polymer/app-layout": "^3.0.1",
     "@polymer/app-localize-behavior": "^3.0.1",
@@ -35,7 +34,6 @@
     "@polymer/iron-media-query": "^3.0.1",
     "@polymer/iron-pages": "^3.0.1",
     "@polymer/iron-resizable-behavior": "^3.0.1",
-    "@polymer/lit-element": "0.6.2",
     "@polymer/neon-animation": "^3.0.1",
     "@polymer/paper-button": "^3.0.1",
     "@polymer/paper-card": "^3.0.1",
@@ -78,7 +76,8 @@
     "jquery": "^3.3.1",
     "js-yaml": "^3.12.0",
     "leaflet": "^1.3.4",
-    "lit-html": "0.12.0",
+    "lit-element": "2.0.0-rc.2",
+    "lit-html": "1.0.0-rc.2",
     "marked": "^0.5.0",
     "mdn-polyfills": "^5.12.0",
     "moment": "^2.22.2",
@@ -158,9 +157,7 @@
     "@webcomponents/shadycss": "^1.6.0",
     "@vaadin/vaadin-overlay": "3.2.2",
     "@vaadin/vaadin-lumo-styles": "1.3.0",
-    "fecha": "https://github.com/taylorhakes/fecha/archive/5e8fe08d982647fdb19fb403459838b02647813c.tar.gz",
+    "fecha": "https://github.com/taylorhakes/fecha/archive/5e8fe08d982647fdb19fb403459838b02647813c.tar.gz"
-    "lit-html": "0.12.0",
-    "@polymer/lit-element": "0.6.2"
   },
   "main": "src/home-assistant.js",
   "husky": {

src/auth/ha-authorize.ts

@@ -1,5 +1,5 @@
 import { litLocalizeLiteMixin } from "../mixins/lit-localize-lite-mixin";
-import { LitElement, html, PropertyDeclarations } from "@polymer/lit-element";
+import { LitElement, html, PropertyDeclarations } from "lit-element";
 import "./ha-auth-flow";
 import { AuthProvider } from "../data/auth";
 
@@ -50,7 +50,7 @@ class HaAuthorize extends litLocalizeLiteMixin(LitElement) {
     };
   }
 
-  public render() {
+  protected render() {
     if (!this._authProviders) {
       return html`
         <p>[[localize('ui.panel.page-authorize.initializing')]]</p>

src/components/buttons/ha-call-api-button.js

@@ -1,4 +1,4 @@
-import { LitElement, html } from "@polymer/lit-element";
+import { LitElement, html } from "lit-element";
 
 import "./ha-progress-button";
 import { fireEvent } from "../../common/dom/fire_event";

src/components/entity/ha-state-label-badge.ts

@@ -3,10 +3,10 @@ import {
   html,
   PropertyValues,
   PropertyDeclarations,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 import { HassEntity } from "home-assistant-js-websocket";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
 
 import computeStateDomain from "../../common/entity/compute_state_domain";
 import computeStateName from "../../common/entity/compute_state_name";
@@ -41,7 +41,7 @@ export class HaStateLabelBadge extends hassLocalizeLitMixin(LitElement) {
     this.clearInterval();
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     const state = this.state;
 
     if (!state) {

src/components/ha-label-badge.ts

@@ -1,10 +1,11 @@
 import {
+  html,
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult, html } from "lit-html";
+} from "lit-element";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
 import "./ha-icon";
 
 class HaLabelBadge extends LitElement {
@@ -24,7 +25,7 @@ class HaLabelBadge extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <div class="badge-container">

src/layouts/app/dialog-manager-mixin.ts

@@ -1,5 +1,5 @@
 import { PolymerElement } from "@polymer/polymer";
-import { Constructor } from "@polymer/lit-element";
+import { Constructor } from "lit-element";
 import { HASSDomEvent, ValidHassDomEvent } from "../../common/dom/fire_event";
 
 interface RegisterDialogParams {

src/layouts/app/home-assistant.js

@@ -4,7 +4,7 @@ import "@polymer/iron-flex-layout/iron-flex-layout-classes";
 import { html } from "@polymer/polymer/lib/utils/html-tag";
 import { PolymerElement } from "@polymer/polymer/polymer-element";
 import { afterNextRender } from "@polymer/polymer/lib/utils/render-status";
-import { html as litHtml, LitElement } from "@polymer/lit-element";
+import { html as litHtml, LitElement } from "lit-element";
 
 import "../home-assistant-main";
 import "../ha-init-page";

src/mixins/lit-localize-lite-mixin.ts

@@ -3,7 +3,7 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+} from "lit-element";
 import { HomeAssistant } from "../types";
 import { getActiveTranslation } from "../util/hass-translation";
 import { LocalizeFunc, LocalizeMixin } from "./localize-base-mixin";

src/mixins/lit-localize-mixin.ts

@@ -3,7 +3,7 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+} from "lit-element";
 import { HomeAssistant } from "../types";
 import {
   localizeBaseMixin,

src/panels/config/cloud/cloud-alexa-pref.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-card/paper-card";
 import "@polymer/paper-toggle-button/paper-toggle-button";
@@ -23,7 +27,7 @@ export class CloudAlexaPref extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.cloudStatus) {
       return html``;
     }

src/panels/config/cloud/cloud-exposed-entities.ts

@@ -3,8 +3,8 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 import { repeat } from "lit-html/directives/repeat";
 import "@polymer/paper-tooltip/paper-tooltip";
 import { HassEntityBase } from "home-assistant-js-websocket";
@@ -34,7 +34,7 @@ export class CloudExposedEntities extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._filterFunc) {
       return html``;
     }

src/panels/config/cloud/cloud-google-pref.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-card/paper-card";
 import "@polymer/paper-toggle-button/paper-toggle-button";
@@ -24,7 +28,7 @@ export class CloudGooglePref extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.cloudStatus) {
       return html``;
     }

src/panels/config/cloud/cloud-webhook-manage-dialog.ts

@@ -1,4 +1,4 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import { html, LitElement, PropertyDeclarations } from "lit-element";
 
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-input/paper-input";

src/panels/config/cloud/cloud-webhooks.ts

@@ -3,7 +3,7 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+} from "lit-element";
 import "@polymer/paper-toggle-button/paper-toggle-button";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-item/paper-item-body";

src/panels/config/zha/ha-config-zha.ts

@@ -1,10 +1,14 @@
 import "@polymer/app-layout/app-header/app-header";
 import "@polymer/app-layout/app-toolbar/app-toolbar";
 import "@polymer/iron-flex-layout/iron-flex-layout-classes";
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-icon-button/paper-icon-button";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
 import { HASSDomEvent } from "../../../common/dom/fire_event";
 import { Cluster } from "../../../data/zha";
 import "../../../layouts/ha-app-layout";
@@ -39,7 +43,7 @@ export class HaConfigZha extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <ha-app-layout>

src/panels/config/zha/zha-cluster-attributes.ts

@@ -4,12 +4,12 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-card/paper-card";
 import "@polymer/paper-icon-button/paper-icon-button";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
 import "../../../components/buttons/ha-call-service-button";
 import "../../../components/ha-service-description";
 import {
@@ -78,7 +78,7 @@ export class ZHAClusterAttributes extends LitElement {
     super.update(changedProperties);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <ha-config-section .isWide="${this.isWide}">

src/panels/config/zha/zha-cluster-commands.ts

@@ -4,10 +4,10 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-card/paper-card";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
 import "../../../components/buttons/ha-call-service-button";
 import "../../../components/ha-service-description";
 import {
@@ -70,7 +70,7 @@ export class ZHAClusterCommands extends LitElement {
     super.update(changedProperties);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <ha-config-section .isWide="${this.isWide}">

src/panels/config/zha/zha-clusters.ts

@@ -4,9 +4,9 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-card/paper-card";
-import { TemplateResult } from "lit-html";
 import { fireEvent } from "../../../common/dom/fire_event";
 import "../../../components/buttons/ha-call-service-button";
 import "../../../components/ha-service-description";
@@ -73,7 +73,7 @@ export class ZHAClusters extends LitElement {
     super.update(changedProperties);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this._renderStyle()}
       <div class="node-picker">

src/panels/config/zha/zha-entities.ts

@@ -4,12 +4,12 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
 import { fireEvent } from "../../../common/dom/fire_event";
 import { fetchEntitiesForZhaNode } from "../../../data/zha";
 import "../../../resources/ha-style";
@@ -62,7 +62,7 @@ export class ZHAEntities extends LitElement {
     super.update(changedProperties);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this._renderStyle()}
       <div class="node-picker">

src/panels/config/zha/zha-network.ts

@@ -1,9 +1,13 @@
 import "@polymer/iron-flex-layout/iron-flex-layout-classes";
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-card/paper-card";
 import "@polymer/paper-icon-button/paper-icon-button";
-import { TemplateResult } from "lit-html";
 import "../../../components/buttons/ha-call-service-button";
 import "../../../components/ha-service-description";
 import "../../../resources/ha-style";
@@ -30,7 +34,7 @@ export class ZHANetwork extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <ha-config-section .isWide="${this.isWide}">

src/panels/config/zha/zha-node.ts

@@ -1,12 +1,16 @@
 import "@polymer/iron-flex-layout/iron-flex-layout-classes";
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-card/paper-card";
 import "@polymer/paper-icon-button/paper-icon-button";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
 import { fireEvent, HASSDomEvent } from "../../../common/dom/fire_event";
 import computeStateName from "../../../common/entity/compute_state_name";
 import sortByName from "../../../common/entity/states_sort_by_name";
@@ -64,7 +68,7 @@ export class ZHANode extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     this._nodes = this._computeNodes(this.hass);
     return html`
       ${this.renderStyle()}

src/panels/lovelace/cards/hui-alarm-panel-card.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyValues,
   PropertyDeclarations,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
 
 import { LovelaceCard } from "../types";
 import { HomeAssistant } from "../../../types";
@@ -97,7 +97,7 @@ class HuiAlarmPanelCard extends hassLocalizeLitMixin(LitElement)
     return true;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-entities-card.ts

@@ -3,8 +3,8 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 
 import "../../../components/ha-card";
 import "../components/hui-entities-toggle";
@@ -95,7 +95,7 @@ class HuiEntitiesCard extends hassLocalizeLitMixin(LitElement)
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this._hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-entity-button-card.ts

@@ -3,10 +3,10 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
+} from "lit-element";
 import { HassEntity } from "home-assistant-js-websocket";
-import { TemplateResult } from "lit-html";
+import { styleMap } from "lit-html/directives/style-map";
-import { styleMap } from "lit-html/directives/styleMap";
 
 import "../../../components/ha-card";
 
@@ -82,7 +82,7 @@ class HuiEntityButtonCard extends hassLocalizeLitMixin(LitElement)
     return true;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-error-card.ts

@@ -1,8 +1,7 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 
 import { LovelaceCard } from "../types";
 import { LovelaceCardConfig } from "../../../data/lovelace";
-import { TemplateResult } from "lit-html";
 import { HomeAssistant } from "../../../types";
 
 interface Config extends LovelaceCardConfig {
@@ -40,7 +39,7 @@ export class HuiErrorCard extends LitElement implements LovelaceCard {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-gauge-card.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
-import { styleMap } from "lit-html/directives/styleMap";
+import { styleMap } from "lit-html/directives/style-map";
 
 import "../../../components/ha-card";
 import { LovelaceCardConfig } from "../../../data/lovelace";
@@ -84,7 +84,7 @@ class HuiGaugeCard extends LitElement implements LovelaceCard {
     this._setBaseUnit();
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-glance-card.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyValues,
   PropertyDeclarations,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
 
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { HomeAssistant } from "../../../types";
@@ -114,7 +114,7 @@ export class HuiGlanceCard extends hassLocalizeLitMixin(LitElement)
     return true;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-horizontal-stack-card.ts

@@ -1,5 +1,4 @@
-import { html } from "@polymer/lit-element";
+import { html, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import { computeCardSize } from "../common/compute-card-size";
 import { HuiStackCard } from "./hui-stack-card";

src/panels/lovelace/cards/hui-iframe-card.ts

@@ -1,11 +1,15 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../../../components/ha-card";
 
 import { LovelaceCard, LovelaceCardEditor } from "../types";
 import { LovelaceCardConfig } from "../../../data/lovelace";
-import { TemplateResult } from "lit-html";
+import { styleMap } from "lit-html/directives/style-map";
-import { styleMap } from "lit-html/directives/styleMap";
 
 export interface Config extends LovelaceCardConfig {
   aspect_ratio?: string;
@@ -42,7 +46,7 @@ export class HuiIframeCard extends LitElement implements LovelaceCard {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-light-card.ts

@@ -3,11 +3,11 @@ import {
   LitElement,
   PropertyValues,
   PropertyDeclarations,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 
 import { fireEvent } from "../../../common/dom/fire_event";
-import { styleMap } from "lit-html/directives/styleMap";
+import { styleMap } from "lit-html/directives/style-map";
 import { HomeAssistant, LightEntity } from "../../../types";
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { LovelaceCard, LovelaceCardEditor } from "../types";
@@ -82,7 +82,7 @@ export class HuiLightCard extends hassLocalizeLitMixin(LitElement)
     this._config = { theme: "default", ...config };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-markdown-card.ts

@@ -1,12 +1,16 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { classMap } from "lit-html/directives/classMap";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
+import { classMap } from "lit-html/directives/class-map";
 
 import "../../../components/ha-card";
 import "../../../components/ha-markdown";
 
 import { LovelaceCard, LovelaceCardEditor } from "../types";
 import { LovelaceCardConfig } from "../../../data/lovelace";
-import { TemplateResult } from "lit-html";
 
 export interface Config extends LovelaceCardConfig {
   content: string;
@@ -42,7 +46,7 @@ export class HuiMarkdownCard extends LitElement implements LovelaceCard {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-picture-card.ts

@@ -1,12 +1,16 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../../../components/ha-card";
 
 import { LovelaceCard, LovelaceCardEditor } from "../types";
 import { LovelaceCardConfig, ActionConfig } from "../../../data/lovelace";
 import { HomeAssistant } from "../../../types";
-import { TemplateResult } from "lit-html";
+import { classMap } from "lit-html/directives/class-map";
-import { classMap } from "lit-html/directives/classMap";
 import { handleClick } from "../common/handle-click";
 import { longPress } from "../common/directives/long-press-directive";
 
@@ -49,7 +53,7 @@ export class HuiPictureCard extends LitElement implements LovelaceCard {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-picture-elements-card.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import { createHuiElement } from "../common/create-hui-element";
 
@@ -55,7 +54,7 @@ class HuiPictureElementsCard extends LitElement implements LovelaceCard {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-picture-entity-card.ts

@@ -1,6 +1,10 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html/lib/shady-render";
+  html,
-import { classMap } from "lit-html/directives/classMap";
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
+import { classMap } from "lit-html/directives/class-map";
 
 import "../../../components/ha-card";
 import "../components/hui-image";
@@ -65,7 +69,7 @@ class HuiPictureEntityCard extends hassLocalizeLitMixin(LitElement)
     this._config = { show_name: true, show_state: true, ...config };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-picture-glance-card.ts

@@ -1,6 +1,10 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { classMap } from "lit-html/directives/classMap";
+  html,
-import { TemplateResult } from "lit-html";
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
+import { classMap } from "lit-html/directives/class-map";
 
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { DOMAINS_TOGGLE } from "../../../common/const";
@@ -83,7 +87,7 @@ class HuiPictureGlanceCard extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-sensor-card.ts

@@ -4,8 +4,8 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 import "@polymer/paper-spinner/paper-spinner";
 
 import { LovelaceCard, LovelaceCardEditor } from "../types";
@@ -192,7 +192,7 @@ class HuiSensorCard extends LitElement implements LovelaceCard {
     return 3;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-shopping-list-card.ts

@@ -1,6 +1,5 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 import { repeat } from "lit-html/directives/repeat";
-import { TemplateResult } from "lit-html";
 import { PaperInputElement } from "@polymer/paper-input/paper-input";
 import "@polymer/paper-checkbox/paper-checkbox";
 
@@ -79,7 +78,7 @@ class HuiShoppingListCard extends hassLocalizeLitMixin(LitElement)
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/cards/hui-stack-card.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import { createCardElement } from "../common/create-card-element";
 
@@ -50,7 +49,7 @@ export abstract class HuiStackCard extends LitElement implements LovelaceCard {
     });
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-thermostat-card.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { classMap } from "lit-html/directives/classMap";
+} from "lit-element";
-import { TemplateResult } from "lit-html";
+import { classMap } from "lit-html/directives/class-map";
 
 import "../../../components/ha-card";
 import "../../../components/ha-icon";
@@ -110,7 +110,7 @@ export class HuiThermostatCard extends hassLocalizeLitMixin(LitElement)
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this._config) {
       return html``;
     }

src/panels/lovelace/cards/hui-vertical-stack-card.ts

@@ -1,8 +1,7 @@
-import { html } from "@polymer/lit-element";
+import { html, TemplateResult } from "lit-element";
 
 import { computeCardSize } from "../common/compute-card-size";
 import { HuiStackCard } from "./hui-stack-card";
-import { TemplateResult } from "lit-html";
 
 class HuiVerticalStackCard extends HuiStackCard {
   public getCardSize() {

src/panels/lovelace/common/has-changed.ts

@@ -1,5 +1,5 @@
 import { HomeAssistant } from "../../../types";
-import { PropertyValues } from "@polymer/lit-element";
+import { PropertyValues } from "lit-element";
 
 // Check if config or Entity changed
 export function hasConfigOrEntityChanged(

src/panels/lovelace/components/hui-action-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-textarea";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
@@ -51,7 +55,7 @@ export class HuiActionEditor extends LitElement {
     return config.service || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this.actions) {
       return html``;
     }

src/panels/lovelace/components/hui-card-options.ts

@@ -1,4 +1,4 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import { html, LitElement, PropertyDeclarations } from "lit-element";
 import "@polymer/paper-button/paper-button";
 import "@polymer/paper-menu-button/paper-menu-button";
 import "@polymer/paper-icon-button/paper-icon-button";

src/panels/lovelace/components/hui-entities-toggle.ts

@@ -3,8 +3,8 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 import { PaperToggleButtonElement } from "@polymer/paper-toggle-button/paper-toggle-button";
 
 import { DOMAINS_TOGGLE } from "../../../common/const";
@@ -35,7 +35,7 @@ class HuiEntitiesToggle extends LitElement {
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._toggleEntities) {
       return html``;
     }

src/panels/lovelace/components/hui-entity-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import { HomeAssistant } from "../../../types";
 import { fireEvent } from "../../../common/dom/fire_event";
@@ -19,7 +23,7 @@ export class HuiEntityEditor extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.entities) {
       return html``;
     }

src/panels/lovelace/components/hui-theme-select-editor.ts

@@ -1,6 +1,10 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-button/paper-button";
-import { TemplateResult } from "lit-html";
 
 import { HomeAssistant } from "../../../types";
 import { fireEvent, HASSDomEvent } from "../../../common/dom/fire_event";
@@ -28,7 +32,7 @@ export class HuiThemeSelectionEditor extends hassLocalizeLitMixin(LitElement) {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     const themes = ["Backend-selected", "default"].concat(
       Object.keys(this.hass!.themes.themes).sort()
     );

src/panels/lovelace/components/hui-timestamp-display.ts

@@ -3,8 +3,8 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
 
 import { HomeAssistant } from "../../../types";
 import format_date from "../../../common/datetime/format_date";
@@ -49,7 +49,7 @@ class HuiTimestampDisplay extends hassLocalizeLitMixin(LitElement) {
     this._clearInterval();
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.ts || !this.hass) {
       return html``;
     }

src/panels/lovelace/editor/card-editor/hui-card-picker.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 import "@polymer/paper-button/paper-button";
 
 import { HomeAssistant } from "../../../../types";
@@ -39,7 +38,7 @@ export class HuiCardPicker extends hassLocalizeLitMixin(LitElement) {
   public hass?: HomeAssistant;
   public cardPicked?: (cardConf: LovelaceCardConfig) => void;
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <h3>${this.localize("ui.panel.lovelace.editor.edit_card.pick_card")}</h3>

src/panels/lovelace/editor/card-editor/hui-dialog-edit-card.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import { HomeAssistant } from "../../../../types";
 import { HASSDomEvent } from "../../../../common/dom/fire_event";
@@ -48,7 +52,7 @@ export class HuiDialogEditCard extends LitElement {
         : undefined;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._params) {
       return html``;
     }

src/panels/lovelace/editor/card-editor/hui-dialog-move-card-view.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-dialog/paper-dialog";
 import "@polymer/paper-item/paper-item";
 // tslint:disable-next-line:no-duplicate-imports
@@ -23,7 +27,7 @@ export class HuiDialogMoveCardView extends hassLocalizeLitMixin(LitElement) {
     await this.updateComplete;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._params) {
       return html``;
     }

src/panels/lovelace/editor/card-editor/hui-dialog-pick-card.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-dialog/paper-dialog";
 import "@polymer/paper-dialog-scrollable/paper-dialog-scrollable";
 
@@ -17,7 +21,7 @@ export class HuiDialogPickCard extends hassLocalizeLitMixin(LitElement) {
     return {};
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       <paper-dialog
         with-backdrop

src/panels/lovelace/editor/card-editor/hui-edit-card.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { classMap } from "lit-html/directives/classMap";
+} from "lit-element";
-import { TemplateResult } from "lit-html";
+import { classMap } from "lit-html/directives/class-map";
 import yaml from "js-yaml";
 
 import "@polymer/paper-spinner/paper-spinner";
@@ -107,7 +107,7 @@ export class HuiEditCard extends hassLocalizeLitMixin(LitElement) {
     this._loadConfigElement(this.cardConfig!);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     let content;
     let preview;
     if (this._configElement !== undefined) {

src/panels/lovelace/editor/card-editor/hui-yaml-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-textarea";
 
 import { HomeAssistant } from "../../../../types";
@@ -21,7 +25,7 @@ export class HuiYAMLEditor extends LitElement {
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <paper-textarea

src/panels/lovelace/editor/config-elements/config-elements-style.ts

@@ -1,4 +1,4 @@
-import { html } from "@polymer/lit-element";
+import { html } from "lit-element";
 
 export const configElementStyle = html`
   <style>

src/panels/lovelace/editor/config-elements/hui-alarm-panel-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
@@ -49,7 +53,7 @@ export class HuiAlarmPanelCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.states || [];
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-entities-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
@@ -62,7 +66,7 @@ export class HuiEntitiesCardEditor extends hassLocalizeLitMixin(LitElement)
     this._configEntities = processEditorEntities(config.entities);
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-entity-button-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -68,7 +72,7 @@ export class HuiEntityButtonCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.theme || "default";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-gauge-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 import "@polymer/paper-toggle-button/paper-toggle-button";
 
@@ -70,7 +74,7 @@ export class HuiGaugeCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.severity || undefined;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-glance-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
@@ -68,7 +72,7 @@ export class HuiGlanceCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.columns || NaN;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-iframe-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -44,7 +48,7 @@ export class HuiIframeCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.aspect_ratio || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-light-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -47,7 +51,7 @@ export class HuiLightCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.entity || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-map-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -64,7 +68,7 @@ export class HuiMapCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.entities || [];
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-markdown-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 import "@polymer/paper-input/paper-textarea";
 
@@ -40,7 +44,7 @@ export class HuiMarkdownCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.content || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-media-control-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import { struct } from "../../common/structs/struct";
 import { EntitiesEditorEvent, EditorTarget } from "../types";
@@ -34,7 +38,7 @@ export class HuiMediaControlCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.entity || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-picture-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -51,7 +55,7 @@ export class HuiPictureCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.hold_action || { action: "none" };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-plant-status-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -42,7 +46,7 @@ export class HuiPlantStatusCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.name || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-sensor-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
@@ -75,7 +79,7 @@ export class HuiSensorCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.hours_to_show || "24";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-shopping-list-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -33,7 +37,7 @@ export class HuiShoppingListEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.title || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-thermostat-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { struct } from "../../common/structs/struct";
@@ -47,7 +51,7 @@ export class HuiThermostatCardEditor extends hassLocalizeLitMixin(LitElement)
     return this._config!.theme || "default";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/config-elements/hui-weather-forecast-card-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import { struct } from "../../common/structs/struct";
 import { EntitiesEditorEvent, EditorTarget } from "../types";
@@ -41,7 +45,7 @@ export class HuiWeatherForecastCardEditor
     return this._config!.name || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/editor/hui-dialog-save-config.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "@polymer/paper-spinner/paper-spinner";
 import "@polymer/paper-dialog/paper-dialog";
@@ -41,7 +45,7 @@ export class HuiSaveConfig extends hassLocalizeLitMixin(LitElement) {
     return this.shadowRoot!.querySelector("paper-dialog")!;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <paper-dialog with-backdrop>

src/panels/lovelace/editor/lovelace-editor/hui-dialog-edit-lovelace.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-spinner/paper-spinner";
 import "@polymer/paper-dialog/paper-dialog";
 // This is not a duplicate import, one is for types, one is for element.
@@ -47,7 +51,7 @@ export class HuiDialogEditLovelace extends hassLocalizeLitMixin(LitElement) {
     return this.shadowRoot!.querySelector("paper-dialog")!;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <paper-dialog with-backdrop>

src/panels/lovelace/editor/lovelace-editor/hui-lovelace-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { EditorTarget } from "../types";
@@ -33,7 +37,7 @@ export class HuiLovelaceEditor extends hassLocalizeLitMixin(LitElement) {
     return this.config.title || "";
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${configElementStyle}
       <div class="card-config">

src/panels/lovelace/editor/view-editor/hui-dialog-edit-view.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import { HomeAssistant } from "../../../../types";
 import { HASSDomEvent } from "../../../../common/dom/fire_event";
@@ -34,7 +38,7 @@ export class HuiDialogEditView extends LitElement {
     (this.shadowRoot!.children[0] as any).showDialog();
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._params) {
       return html``;
     }

src/panels/lovelace/editor/view-editor/hui-edit-view.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "@polymer/paper-spinner/paper-spinner";
 import "@polymer/paper-tabs/paper-tab";
@@ -83,7 +87,7 @@ export class HuiEditView extends hassLocalizeLitMixin(LitElement) {
     return this.shadowRoot!.querySelector("paper-dialog")!;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     let content;
     switch (this._curTab) {
       case "tab-settings":

src/panels/lovelace/editor/view-editor/hui-view-editor.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import "@polymer/paper-input/paper-input";
 
 import { EditorTarget } from "../types";
@@ -59,7 +63,7 @@ export class HuiViewEditor extends hassLocalizeLitMixin(LitElement) {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass) {
       return html``;
     }

src/panels/lovelace/elements/hui-icon-element.ts

@@ -1,4 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 
 import "../../../components/ha-icon";
 
@@ -8,7 +8,6 @@ import { longPress } from "../common/directives/long-press-directive";
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { LovelaceElement, LovelaceElementConfig } from "./types";
 import { HomeAssistant } from "../../../types";
-import { TemplateResult } from "lit-html";
 
 interface Config extends LovelaceElementConfig {
   icon: string;
@@ -31,7 +30,7 @@ export class HuiIconElement extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/elements/hui-image-element.ts

@@ -1,4 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 
 import "../components/hui-image";
 
@@ -8,7 +8,6 @@ import { longPress } from "../common/directives/long-press-directive";
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { LovelaceElement, LovelaceElementConfig } from "./types";
 import { HomeAssistant } from "../../../types";
-import { TemplateResult } from "lit-html";
 
 interface Config extends LovelaceElementConfig {
   image?: string;
@@ -40,7 +39,7 @@ export class HuiImageElement extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/elements/hui-service-button-element.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import "../../../components/buttons/ha-call-service-button";
 
@@ -37,7 +36,7 @@ export class HuiServiceButtonElement extends LitElement
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/elements/hui-state-badge-element.ts

@@ -1,11 +1,10 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 
 import "../../../components/entity/ha-state-label-badge";
 
 import computeStateName from "../../../common/entity/compute_state_name";
 import { LovelaceElement, LovelaceElementConfig } from "./types";
 import { HomeAssistant } from "../../../types";
-import { TemplateResult } from "lit-html";
 
 export class HuiStateBadgeElement extends LitElement
   implements LovelaceElement {
@@ -24,7 +23,7 @@ export class HuiStateBadgeElement extends LitElement
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (
       !this._config ||
       !this.hass ||

src/panels/lovelace/elements/hui-state-icon-element.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import "../../../components/entity/state-badge";
 
@@ -27,7 +26,7 @@ export class HuiStateIconElement extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (
       !this._config ||
       !this.hass ||

src/panels/lovelace/elements/hui-state-label-element.ts

@@ -1,4 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
 
 import "../../../components/entity/ha-state-label-badge";
 
@@ -9,7 +9,6 @@ import { longPress } from "../common/directives/long-press-directive";
 import { hassLocalizeLitMixin } from "../../../mixins/lit-localize-mixin";
 import { LovelaceElement, LovelaceElementConfig } from "./types";
 import { HomeAssistant } from "../../../types";
-import { TemplateResult } from "lit-html";
 
 interface Config extends LovelaceElementConfig {
   prefix?: string;
@@ -33,7 +32,7 @@ class HuiStateLabelElement extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-climate-entity-row.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 import "../../../components/ha-climate-state";
 import "../components/hui-generic-entity-row";
@@ -26,7 +25,7 @@ class HuiClimateEntityRow extends LitElement implements EntityRow {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this._config) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-cover-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../../../components/ha-cover-controls";
@@ -28,7 +32,7 @@ class HuiCoverEntityRow extends LitElement implements EntityRow {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-error-entity-row.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 
 class HuiErrorEntityRow extends LitElement {
   public entity?: string;
@@ -12,7 +11,7 @@ class HuiErrorEntityRow extends LitElement {
     };
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
       ${this.renderStyle()} ${this.error || "Entity not available"}:
       ${this.entity || ""}

src/panels/lovelace/entity-rows/hui-group-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../../../components/entity/ha-entity-toggle";
@@ -30,7 +34,7 @@ class HuiGroupEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-input-select-entity-row.ts

@@ -1,6 +1,10 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import { repeat } from "lit-html/directives/repeat";
-import { TemplateResult } from "lit-html";
 import "@polymer/paper-dropdown-menu/paper-dropdown-menu";
 import "@polymer/paper-item/paper-item";
 import "@polymer/paper-listbox/paper-listbox";
@@ -32,7 +36,7 @@ class HuiInputSelectEntityRow extends LitElement implements EntityRow {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this._config) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-input-text-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 import { PaperInputElement } from "@polymer/paper-input/paper-input";
 
 import "../components/hui-generic-entity-row";
@@ -27,7 +31,7 @@ class HuiInputTextEntityRow extends LitElement implements EntityRow {
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-lock-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "./hui-error-entity-row";
@@ -27,7 +31,7 @@ class HuiLockEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-media-player-entity-row.ts

@@ -1,5 +1,4 @@
-import { html, LitElement } from "@polymer/lit-element";
+import { html, LitElement, TemplateResult } from "lit-element";
-import { TemplateResult } from "lit-html";
 import "@polymer/paper-icon-button/paper-icon-button";
 
 import "../components/hui-generic-entity-row";
@@ -36,7 +35,7 @@ class HuiMediaPlayerEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this.hass || !this._config) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-scene-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../../../components/entity/ha-entity-toggle";
@@ -28,7 +32,7 @@ class HuiSceneEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-script-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../../../components/entity/ha-entity-toggle";
@@ -28,7 +32,7 @@ class HuiScriptEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-sensor-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../components/hui-timestamp-display";
@@ -34,7 +38,7 @@ class HuiSensorEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-text-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "./hui-error-entity-row";
@@ -28,7 +32,7 @@ class HuiTextEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/entity-rows/hui-toggle-entity-row.ts

@@ -1,5 +1,9 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
-import { TemplateResult } from "lit-html";
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "../components/hui-generic-entity-row";
 import "../../../components/entity/ha-entity-toggle";
@@ -29,7 +33,7 @@ class HuiToggleEntityRow extends hassLocalizeLitMixin(LitElement)
     this._config = config;
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this.hass) {
       return html``;
     }

src/panels/lovelace/ha-panel-lovelace.ts

@@ -6,9 +6,8 @@ import "../../layouts/hass-error-screen";
 import "./hui-root";
 import { HomeAssistant, PanelInfo } from "../../types";
 import { Lovelace } from "./types";
-import { LitElement, html, PropertyValues } from "@polymer/lit-element";
+import { LitElement, html, PropertyValues, TemplateResult } from "lit-element";
 import { hassLocalizeLitMixin } from "../../mixins/lit-localize-mixin";
-import { TemplateResult } from "lit-html";
 import { showSaveDialog } from "./editor/show-save-config-dialog";
 import { generateLovelaceConfig } from "./common/generate-lovelace-config";
 
@@ -49,7 +48,7 @@ class LovelacePanel extends hassLocalizeLitMixin(LitElement) {
     this._closeEditor = this._closeEditor.bind(this);
   }
 
-  public render(): TemplateResult {
+  public render(): TemplateResult | void {
     const state = this._state!;
 
     if (state === "loaded") {

src/panels/lovelace/hui-editor.ts

@@ -1,6 +1,5 @@
-import { LitElement, html } from "@polymer/lit-element";
+import { LitElement, html, TemplateResult } from "lit-element";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
-import { TemplateResult } from "lit-html";
 import yaml from "js-yaml";
 
 import "@polymer/app-layout/app-header-layout/app-header-layout";
@@ -43,7 +42,7 @@ class LovelaceFullConfigEditor extends hassLocalizeLitMixin(LitElement) {
     };
   }
 
-  public render(): TemplateResult {
+  public render(): TemplateResult | void {
     return html`
       ${this.renderStyle()}
       <app-header-layout>

src/panels/lovelace/hui-root.ts

@@ -3,9 +3,9 @@ import {
   LitElement,
   PropertyDeclarations,
   PropertyValues,
-} from "@polymer/lit-element";
+  TemplateResult,
-import { TemplateResult } from "lit-html";
+} from "lit-element";
-import { classMap } from "lit-html/directives/classMap";
+import { classMap } from "lit-html/directives/class-map";
 import "@polymer/app-layout/app-header-layout/app-header-layout";
 import "@polymer/app-layout/app-header/app-header";
 import "@polymer/app-layout/app-scroll-effects/effects/waterfall";
@@ -119,7 +119,7 @@ class HUIRoot extends hassLocalizeLitMixin(LitElement) {
     }
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     return html`
     ${this.renderStyle()}
     <app-route .route="${this.route}" pattern="/:view" data="${

src/panels/lovelace/hui-unused-entities.ts

@@ -1,11 +1,15 @@
-import { html, LitElement, PropertyDeclarations } from "@polymer/lit-element";
+import {
+  html,
+  LitElement,
+  PropertyDeclarations,
+  TemplateResult,
+} from "lit-element";
 
 import "./cards/hui-entities-card";
 
 import { computeUnusedEntities } from "./common/compute-unused-entities";
 import { createCardElement } from "./common/create-card-element";
 import { HomeAssistant } from "../../types";
-import { TemplateResult } from "lit-html";
 import { LovelaceCard } from "./types";
 import { LovelaceConfig } from "../../data/lovelace";
 
@@ -35,7 +39,7 @@ export class HuiUnusedEntities extends LitElement {
     this._createElement();
   }
 
-  protected render(): TemplateResult {
+  protected render(): TemplateResult | void {
     if (!this._config || !this._hass) {
       return html``;
     }