diff --git a/package.json b/package.json
index a7c3450adc..cc40b5b357 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
   "version": "1.0.0",
   "scripts": {
     "build": "script/build_frontend",
-    "lint": "eslint src hassio/src gallery/src test-mocha && tslint -c tslint.json 'src/**/*.ts' 'hassio/src/**/*.ts' 'gallery/src/**/*.ts' 'test-mocha/**/*.ts' && polymer lint",
+    "lint": "eslint src hassio/src gallery/src test-mocha && tslint -c tslint.json 'src/**/*.ts' 'hassio/src/**/*.ts' 'gallery/src/**/*.ts' 'test-mocha/**/*.ts' && polymer lint && tsc",
     "mocha": "node_modules/.bin/mocha --opts test-mocha/mocha.opts",
     "test": "npm run lint && npm run mocha",
     "docker_build": "sh ./script/docker_run.sh build $npm_package_version",
diff --git a/src/mixins/lit-localize-mixin.ts b/src/mixins/lit-localize-mixin.ts
index 51c408310a..36a2bc1596 100644
--- a/src/mixins/lit-localize-mixin.ts
+++ b/src/mixins/lit-localize-mixin.ts
@@ -16,8 +16,8 @@ export const HassLocalizeLitMixin = (
 ): Constructor<LitElement & LocalizeMixin> =>
   // @ts-ignore
   class extends LocalizeBaseMixin(superClass) {
-    protected hass: HomeAssistant;
-    protected localize: LocalizeFunc;
+    protected hass?: HomeAssistant;
+    protected localize?: LocalizeFunc;
 
     static get properties(): PropertyDeclarations {
       return {
diff --git a/src/mixins/localize-base-mixin.ts b/src/mixins/localize-base-mixin.ts
index af19f90ae4..a3c8f6b6ab 100644
--- a/src/mixins/localize-base-mixin.ts
+++ b/src/mixins/localize-base-mixin.ts
@@ -1,4 +1,3 @@
-import { dedupingMixin } from "@polymer/polymer/lib/utils/mixin.js";
 import IntlMessageFormat from "intl-messageformat/src/main.js";
 
 /**
diff --git a/src/panels/lovelace/cards/hui-glance-card.ts b/src/panels/lovelace/cards/hui-glance-card.ts
index 5154848ea6..6f9f4fe5e8 100644
--- a/src/panels/lovelace/cards/hui-glance-card.ts
+++ b/src/panels/lovelace/cards/hui-glance-card.ts
@@ -42,9 +42,9 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
       hass: {},
     };
   }
-  protected hass: HomeAssistant;
-  protected config: Config;
-  protected configEntities: EntityConfig[];
+  protected hass?: HomeAssistant;
+  protected config?: Config;
+  protected configEntities?: EntityConfig[];
 
   public getCardSize() {
     return 3;
@@ -52,6 +52,16 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
 
   public setConfig(config: Config) {
     this.config = config;
+    const entities = processConfigEntities(config.entities);
+
+    for (const entity of entities) {
+      if (entity.tap_action === "call-service" && !entity.service) {
+        throw new Error(
+          'Missing required property "service" when tap_action is call-service'
+        );
+      }
+    }
+
     this.style.setProperty(
       "--glance-column-width",
       config.column_width || "20%"
@@ -64,19 +74,20 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
       this.classList.add(`theme-${config.theming}`);
     }
 
-    this.configEntities = processConfigEntities(config.entities);
+    this.configEntities = entities;
+
     if (this.hass) {
       this.requestUpdate();
     }
   }
 
   protected render() {
-    if (!this.config) {
+    if (!this.config || !this.hass) {
       return html``;
     }
     const { title } = this.config;
     const states = this.hass.states;
-    const entities = this.configEntities.filter(
+    const entities = this.configEntities!.filter(
       (conf) => conf.entity in states
     );
 
@@ -138,7 +149,7 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
   }
 
   private renderEntity(entityConf) {
-    const stateObj = this.hass.states[entityConf.entity];
+    const stateObj = this.hass!.states[entityConf.entity];
 
     return html`
       <div
@@ -147,7 +158,7 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
         @click="${this.handleClick}"
       >
         ${
-          this.config.show_name !== false
+          this.config!.show_name !== false
             ? html`<div class="name">${
                 "name" in entityConf
                   ? entityConf.name
@@ -160,7 +171,7 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
           .overrideIcon="${entityConf.icon}"
         ></state-badge>
         ${
-          this.config.show_state !== false
+          this.config!.show_state !== false
             ? html`<div>${computeStateDisplay(this.localize, stateObj)}</div>`
             : ""
         }
@@ -176,9 +187,9 @@ class HuiGlanceCard extends HassLocalizeLitMixin(LitElement)
         toggleEntity(this.hass, entityId);
         break;
       case "call-service": {
-        const [domain, service] = config.service.split(".", 2);
+        const [domain, service] = config.service!.split(".", 2);
         const serviceData = { entity_id: entityId, ...config.service_data };
-        this.hass.callService(domain, service, serviceData);
+        this.hass!.callService(domain, service, serviceData);
         break;
       }
       default: