diff --git a/.gitignore b/.gitignore
index 2548df4..0f21f19 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 /node_modules/
 /yarn.lock
-/.rpt2_cache/
+/.tsbuildinfo
 /dist/
diff --git a/.prettierrc.js b/.prettierrc.js
index 93f1e1c..4121004 100644
--- a/.prettierrc.js
+++ b/.prettierrc.js
@@ -4,4 +4,4 @@ module.exports = {
     singleQuote: true,
     printWidth: 120,
     tabWidth: 2,
-};
\ No newline at end of file
+};
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 30caed5..6465cd3 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -6,13 +6,21 @@ import globals from 'globals';
 
 export default ts.config(
   js.configs.recommended,
-  ts.configs.recommended,
+  ts.configs.strictTypeChecked,
+  ts.configs.stylisticTypeChecked,
   {
     rules: {
       '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-unused-vars': ['warn', {'argsIgnorePattern': '^_'}],
+      '@typescript-eslint/no-unsafe-assignment': 'off',
+      '@typescript-eslint/no-unsafe-member-access': 'off',
+      '@typescript-eslint/no-unsafe-call': 'off',
     },
     languageOptions: {
       sourceType: 'module',  // Allows for the use of imports
+      globals: {
+        ...globals.browser,
+      },
       parserOptions: {
         tsconfigRootDir: import.meta.dirname,
         projectService: true,  // TypeScript type checking service
diff --git a/package-lock.json b/package-lock.json
index cb57ddc..21d85bf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -13,11 +13,12 @@
         "lit": "^2.8.0"
       },
       "devDependencies": {
+        "@rollup/plugin-eslint": "^9.0.5",
         "@rollup/plugin-node-resolve": "^15.3.0",
-        "eslint": "^9.20.1",
+        "@rollup/plugin-typescript": "^12.1.2",
         "rollup": "^4.24.3",
         "rollup-plugin-serve": "^3.0.0",
-        "rollup-plugin-typescript2": "^0.36.0",
+        "tslib": "^2.8.1",
         "typescript": "~5.7.3",
         "typescript-eslint": "^8.24.0"
       }
@@ -327,6 +328,28 @@
         "node": ">= 8"
       }
     },
+    "node_modules/@rollup/plugin-eslint": {
+      "version": "9.0.5",
+      "resolved": "https://registry.npmjs.org/@rollup/plugin-eslint/-/plugin-eslint-9.0.5.tgz",
+      "integrity": "sha512-C4nh0sSeJuxVW5u5tDX+dCMjKcNfHm4hS+zeUVh1si7gttnhgGbrmPkUxIX7iZgYABwdEh/ewyMbZB+WXjSJdA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@rollup/pluginutils": "^5.0.1",
+        "eslint": "^8.24.0"
+      },
+      "engines": {
+        "node": ">=14.0.0"
+      },
+      "peerDependencies": {
+        "rollup": "^1.20.0||^2.0.0||^3.0.0||^4.0.0"
+      },
+      "peerDependenciesMeta": {
+        "rollup": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@rollup/plugin-node-resolve": {
       "version": "15.3.1",
       "resolved": "https://registry.npmjs.org/@rollup/plugin-node-resolve/-/plugin-node-resolve-15.3.1.tgz",
@@ -352,6 +375,33 @@
         }
       }
     },
+    "node_modules/@rollup/plugin-typescript": {
+      "version": "12.1.2",
+      "resolved": "https://registry.npmjs.org/@rollup/plugin-typescript/-/plugin-typescript-12.1.2.tgz",
+      "integrity": "sha512-cdtSp154H5sv637uMr1a8OTWB0L1SWDSm1rDGiyfcGcvQ6cuTs4MDk2BVEBGysUWago4OJN4EQZqOTl/QY3Jgg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@rollup/pluginutils": "^5.1.0",
+        "resolve": "^1.22.1"
+      },
+      "engines": {
+        "node": ">=14.0.0"
+      },
+      "peerDependencies": {
+        "rollup": "^2.14.0||^3.0.0||^4.0.0",
+        "tslib": "*",
+        "typescript": ">=3.7.0"
+      },
+      "peerDependenciesMeta": {
+        "rollup": {
+          "optional": true
+        },
+        "tslib": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@rollup/pluginutils": {
       "version": "5.1.4",
       "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-5.1.4.tgz",
@@ -790,13 +840,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/commondir": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/commondir/-/commondir-1.0.1.tgz",
-      "integrity": "sha512-W9pAhw0ja1Edb5GVdIF1mjZw/ASI0AlShXM83UUGe2DVr5TdAPEA1OA8m/g8zWp9x6On7gqufY+FatDbC3MDQg==",
-      "dev": true,
-      "license": "MIT"
-    },
     "node_modules/concat-map": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
@@ -1193,24 +1236,6 @@
         "node": ">=8"
       }
     },
-    "node_modules/find-cache-dir": {
-      "version": "3.3.2",
-      "resolved": "https://registry.npmjs.org/find-cache-dir/-/find-cache-dir-3.3.2.tgz",
-      "integrity": "sha512-wXZV5emFEjrridIgED11OoUKLxiYjAcqot/NJdAkOhlJ+vGzwhOAfcG5OX1jP+S0PcjEn8bdMJv+g2jwQ3Onig==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "commondir": "^1.0.1",
-        "make-dir": "^3.0.2",
-        "pkg-dir": "^4.1.0"
-      },
-      "engines": {
-        "node": ">=8"
-      },
-      "funding": {
-        "url": "https://github.com/avajs/find-cache-dir?sponsor=1"
-      }
-    },
     "node_modules/find-up": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/find-up/-/find-up-5.0.0.tgz",
@@ -1249,21 +1274,6 @@
       "dev": true,
       "license": "ISC"
     },
-    "node_modules/fs-extra": {
-      "version": "10.1.0",
-      "resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-10.1.0.tgz",
-      "integrity": "sha512-oRXApq54ETRj4eMiFzGnHWGy+zo5raudjuxN0b8H7s/RU2oW0Wvsx9O0ACRN/kRq9E8Vu/ReskGB5o3ji+FzHQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "graceful-fs": "^4.2.0",
-        "jsonfile": "^6.0.1",
-        "universalify": "^2.0.0"
-      },
-      "engines": {
-        "node": ">=12"
-      }
-    },
     "node_modules/function-bind": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.2.tgz",
@@ -1300,13 +1310,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/graceful-fs": {
-      "version": "4.2.11",
-      "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.2.11.tgz",
-      "integrity": "sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==",
-      "dev": true,
-      "license": "ISC"
-    },
     "node_modules/graphemer": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/graphemer/-/graphemer-1.4.0.tgz",
@@ -1489,19 +1492,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/jsonfile": {
-      "version": "6.1.0",
-      "resolved": "https://registry.npmjs.org/jsonfile/-/jsonfile-6.1.0.tgz",
-      "integrity": "sha512-5dgndWOriYSm5cnYaJNhalLNDKOqFwyDB/rr1E9ZsGciGvKPs8R2xYGCacuf3z6K1YKDz182fd+fY3cn3pMqXQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "universalify": "^2.0.0"
-      },
-      "optionalDependencies": {
-        "graceful-fs": "^4.1.6"
-      }
-    },
     "node_modules/keyv": {
       "version": "4.5.4",
       "resolved": "https://registry.npmjs.org/keyv/-/keyv-4.5.4.tgz",
@@ -1580,32 +1570,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/make-dir": {
-      "version": "3.1.0",
-      "resolved": "https://registry.npmjs.org/make-dir/-/make-dir-3.1.0.tgz",
-      "integrity": "sha512-g3FeP20LNwhALb/6Cz6Dd4F2ngze0jz7tbzrD2wAV+o9FeNHe4rL+yK2md0J/fiSf1sa1ADhXqi5+oVwOM/eGw==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "semver": "^6.0.0"
-      },
-      "engines": {
-        "node": ">=8"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
-    "node_modules/make-dir/node_modules/semver": {
-      "version": "6.3.1",
-      "resolved": "https://registry.npmjs.org/semver/-/semver-6.3.1.tgz",
-      "integrity": "sha512-BR7VvDCVHO+q2xBEWskxS6DJE1qRnb7DxzUrogb71CWoSficBxYsiAGd+Kl0mmq/MprG9yArRkyrQxTO6XjMzA==",
-      "dev": true,
-      "license": "ISC",
-      "bin": {
-        "semver": "bin/semver.js"
-      }
-    },
     "node_modules/merge2": {
       "version": "1.4.1",
       "resolved": "https://registry.npmjs.org/merge2/-/merge2-1.4.1.tgz",
@@ -1746,16 +1710,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/p-try": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/p-try/-/p-try-2.2.0.tgz",
-      "integrity": "sha512-R4nPAVTAU0B9D35/Gk3uJf/7XYbQcyohSKdvAxIRSNghFl4e71hVoGnBNQz9cWaXxO2I10KTC+3jMdvvoKw6dQ==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=6"
-      }
-    },
     "node_modules/parent-module": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/parent-module/-/parent-module-1.0.1.tgz",
@@ -1809,75 +1763,6 @@
         "url": "https://github.com/sponsors/jonschlinkert"
       }
     },
-    "node_modules/pkg-dir": {
-      "version": "4.2.0",
-      "resolved": "https://registry.npmjs.org/pkg-dir/-/pkg-dir-4.2.0.tgz",
-      "integrity": "sha512-HRDzbaKjC+AOWVXxAU/x54COGeIv9eb+6CkDSQoNTt4XyWoIJvuPsXizxu/Fr23EiekbtZwmh1IcIG/l/a10GQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "find-up": "^4.0.0"
-      },
-      "engines": {
-        "node": ">=8"
-      }
-    },
-    "node_modules/pkg-dir/node_modules/find-up": {
-      "version": "4.1.0",
-      "resolved": "https://registry.npmjs.org/find-up/-/find-up-4.1.0.tgz",
-      "integrity": "sha512-PpOwAdQ/YlXQ2vj8a3h8IipDuYRi3wceVQQGYWxNINccq40Anw7BlsEXCMbt1Zt+OLA6Fq9suIpIWD0OsnISlw==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "locate-path": "^5.0.0",
-        "path-exists": "^4.0.0"
-      },
-      "engines": {
-        "node": ">=8"
-      }
-    },
-    "node_modules/pkg-dir/node_modules/locate-path": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/locate-path/-/locate-path-5.0.0.tgz",
-      "integrity": "sha512-t7hw9pI+WvuwNJXwk5zVHpyhIqzg2qTlklJOf0mVxGSbe3Fp2VieZcduNYjaLDoy6p9uGpQEGWG87WpMKlNq8g==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "p-locate": "^4.1.0"
-      },
-      "engines": {
-        "node": ">=8"
-      }
-    },
-    "node_modules/pkg-dir/node_modules/p-limit": {
-      "version": "2.3.0",
-      "resolved": "https://registry.npmjs.org/p-limit/-/p-limit-2.3.0.tgz",
-      "integrity": "sha512-//88mFWSJx8lxCzwdAABTJL2MyWB12+eIY7MDL2SqLmAkeKU9qxRvWuSyTjm3FUmpBEMuFfckAIqEaVGUDxb6w==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "p-try": "^2.0.0"
-      },
-      "engines": {
-        "node": ">=6"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
-    "node_modules/pkg-dir/node_modules/p-locate": {
-      "version": "4.1.0",
-      "resolved": "https://registry.npmjs.org/p-locate/-/p-locate-4.1.0.tgz",
-      "integrity": "sha512-R79ZZ/0wAxKGu3oYMlz8jy/kbhsNrS7SKZ7PxEHBgJ5+F2mtFW2fK2cOtBh1cHYkQsbzFV7I+EoRKe6Yt0oK7A==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "p-limit": "^2.2.0"
-      },
-      "engines": {
-        "node": ">=8"
-      }
-    },
     "node_modules/prelude-ls": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
@@ -2011,51 +1896,6 @@
         "opener": "1"
       }
     },
-    "node_modules/rollup-plugin-typescript2": {
-      "version": "0.36.0",
-      "resolved": "https://registry.npmjs.org/rollup-plugin-typescript2/-/rollup-plugin-typescript2-0.36.0.tgz",
-      "integrity": "sha512-NB2CSQDxSe9+Oe2ahZbf+B4bh7pHwjV5L+RSYpCu7Q5ROuN94F9b6ioWwKfz3ueL3KTtmX4o2MUH2cgHDIEUsw==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "@rollup/pluginutils": "^4.1.2",
-        "find-cache-dir": "^3.3.2",
-        "fs-extra": "^10.0.0",
-        "semver": "^7.5.4",
-        "tslib": "^2.6.2"
-      },
-      "peerDependencies": {
-        "rollup": ">=1.26.3",
-        "typescript": ">=2.4.0"
-      }
-    },
-    "node_modules/rollup-plugin-typescript2/node_modules/@rollup/pluginutils": {
-      "version": "4.2.1",
-      "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-4.2.1.tgz",
-      "integrity": "sha512-iKnFXr7NkdZAIHiIWE+BX5ULi/ucVFYWD6TbAV+rZctiRTY2PL6tsIKhoIOaoskiWAkgu+VsbXgUVDNLHf+InQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "estree-walker": "^2.0.1",
-        "picomatch": "^2.2.2"
-      },
-      "engines": {
-        "node": ">= 8.0.0"
-      }
-    },
-    "node_modules/rollup-plugin-typescript2/node_modules/picomatch": {
-      "version": "2.3.1",
-      "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.3.1.tgz",
-      "integrity": "sha512-JU3teHTNjmE2VCGFzuY8EXzCDVwEqB2a8fsIvwaStHhAWJEeVd1o1QD80CU6+ZdEXXSLbSsuLwJjkCBWqRQUVA==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=8.6"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/jonschlinkert"
-      }
-    },
     "node_modules/run-parallel": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/run-parallel/-/run-parallel-1.2.0.tgz",
@@ -2243,16 +2083,6 @@
         "typescript": ">=4.8.4 <5.8.0"
       }
     },
-    "node_modules/universalify": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/universalify/-/universalify-2.0.1.tgz",
-      "integrity": "sha512-gptHNQghINnc/vTGIk0SOFGFNXw7JVrlRUtConJRlvaw6DuX0wO5Jeko9sWrMBhh+PsYAZ7oXAiOnf/UKogyiw==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">= 10.0.0"
-      }
-    },
     "node_modules/uri-js": {
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",
diff --git a/package.json b/package.json
index 808df24..82760c3 100644
--- a/package.json
+++ b/package.json
@@ -21,16 +21,21 @@
   "devDependencies": {
     "rollup": "^4.24.3",
     "@rollup/plugin-node-resolve": "^15.3.0",
-    "rollup-plugin-typescript2": "^0.36.0",
+    "@rollup/plugin-eslint": "^9.0.5",
+    "typescript-eslint": "^8.24.0",
+    "@rollup/plugin-typescript": "^12.1.2",
     "typescript": "~5.7.3",
-    "rollup-plugin-serve": "^3.0.0",
-    "eslint": "^9.20.1",
-    "typescript-eslint": "^8.24.0"
+    "tslib": "^2.8.1",
+    "rollup-plugin-serve": "^3.0.0"
+  },
+  "overrides": {
+    "@rollup/plugin-eslint": {
+      "eslint": "^9.20.1"
+    }
   },
   "scripts": {
-    "start": "rollup -c rollup.config.dev.mjs --watch",
-    "build": "npm run lint && npm run rollup",
-    "lint": "eslint src/*.ts",
-    "rollup": "rollup -c"
+    "devl": "rollup --config --watch",
+    "build": "rollup --config",
+    "lint": "eslint"
   }
 }
diff --git a/rollup.config.dev.mjs b/rollup.config.dev.mjs
deleted file mode 100644
index 8ea544c..0000000
--- a/rollup.config.dev.mjs
+++ /dev/null
@@ -1,31 +0,0 @@
-import resolve from '@rollup/plugin-node-resolve';
-import typescript from 'rollup-plugin-typescript2';
-import serve from 'rollup-plugin-serve';
-
-export default {
-  input: ['src/config-template-card.ts'],
-  output: {
-    dir: './dist',
-    format: 'es',
-  },
-  plugins: [
-    resolve(),
-    typescript(),
-    serve({
-      contentBase: './dist',
-      host: '0.0.0.0',
-      port: 5000,
-      allowCrossOrigin: true,
-      headers: {
-        'Access-Control-Allow-Origin': '*',
-      },
-    }),
-  ], treeshake: false,
-  moduleContext: {
-    // intl-utils is deprecated but still used by custom-card-helpers.
-    // Until it is removed from custom-card-helpers, silence a Rollup warning related to it:
-    // https://rollupjs.org/troubleshooting/#error-this-is-undefined
-    'node_modules/@formatjs/intl-utils/lib/src/diff.js': 'window',
-    'node_modules/@formatjs/intl-utils/lib/src/resolve-locale.js': 'window',
-  },
-};
diff --git a/rollup.config.mjs b/rollup.config.mjs
index 7a1d4de..f9b77b2 100644
--- a/rollup.config.mjs
+++ b/rollup.config.mjs
@@ -1,15 +1,33 @@
-import resolve from '@rollup/plugin-node-resolve';
-import typescript from 'rollup-plugin-typescript2';
+import { nodeResolve } from '@rollup/plugin-node-resolve';
+import eslint from '@rollup/plugin-eslint';
+import typescript from '@rollup/plugin-typescript';
+
+const watch = process.env.ROLLUP_WATCH;
 
 export default {
   input: ['src/config-template-card.ts'],
   output: {
     dir: './dist',
     format: 'es',
+    sourcemap: true,
   },
   plugins: [
-    resolve(),
-    typescript(),
+    nodeResolve(),
+    eslint({
+      throwOnError: false,
+    }),
+    typescript({
+      noEmitOnError: true,
+    }),
+    watch && serve({
+      contentBase: './dist',
+      host: '0.0.0.0',
+      port: 5000,
+      allowCrossOrigin: true,
+      headers: {
+        'Access-Control-Allow-Origin': '*',
+      },
+    }),
   ], treeshake: false,
   moduleContext: {
     // intl-utils is deprecated but still used by custom-card-helpers.
diff --git a/src/config-template-card.ts b/src/config-template-card.ts
index 22fa959..916e2c3 100644
--- a/src/config-template-card.ts
+++ b/src/config-template-card.ts
@@ -6,7 +6,6 @@ import { ConfigTemplateConfig, ConfigTemplateVars } from './types';
 import { CARD_VERSION } from './const';
 import { isString } from './util';
 
-/* eslint no-console: 0 */
 console.info(
   `%c  CONFIG-TEMPLATE-CARD  \n%c  Version ${CARD_VERSION}         `,
   'color: orange; font-weight: bold; background: black',
@@ -21,7 +20,7 @@ export class ConfigTemplateCard extends LitElement {
   @state() private _helpers?: any;
   private _initialized = false;
 
-  public setConfig(config: ConfigTemplateConfig): void {
+  public setConfig(config?: ConfigTemplateConfig): void {
     if (!config) {
       throw new Error('Invalid configuration');
     }
@@ -50,10 +49,10 @@ export class ConfigTemplateCard extends LitElement {
 
     this._config = config;
 
-    this.loadCardHelpers();
+    void this.loadCardHelpers();
   }
 
-  private getLovelacePanel() {
+  private getLovelacePanel(): any {
     const ha = document.querySelector('home-assistant');
     if (ha?.shadowRoot) {
       const haMain = ha.shadowRoot.querySelector('home-assistant-main');
@@ -64,8 +63,8 @@ export class ConfigTemplateCard extends LitElement {
     return null;
   }
 
-  private getLovelaceConfig() {
-    const panel = this.getLovelacePanel() as any;
+  private getLovelaceConfig(): any {
+    const panel = this.getLovelacePanel();
 
     if (panel?.lovelace?.config?.config_template_card_vars) {
       return panel.lovelace.config.config_template_card_vars;
@@ -102,17 +101,20 @@ export class ConfigTemplateCard extends LitElement {
 
   public getCardSize(): number | Promise<number> {
     if (this.shadowRoot) {
-      const element = this.shadowRoot.querySelector('#card > *') as LovelaceCard;
+      // eslint detects this assertion as unnecessary, but typescript requires it.
+      // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
+      const element = this.shadowRoot.querySelector('#card > *') as LovelaceCard | null;
       if (element) {
-        console.log('computeCardSize is ' + computeCardSize(element));
+        Promise.resolve(computeCardSize(element)).then((size) => {
+          console.log('computeCardSize is ' + size.toString());
+        }, () => undefined);
         return computeCardSize(element);
       }
     }
-
     return 1;
   }
 
-  protected render(): TemplateResult | void {
+  protected render(): TemplateResult {
     if (
       !this._config ||
       !this.hass ||
@@ -135,9 +137,7 @@ export class ConfigTemplateCard extends LitElement {
     if (!this._curVars) { this._evaluateVars(); }
 
     configSection = this._evaluateStructure(configSection);
-    if (style) {
-      style = this._evaluateStructure(style);
-    }
+    style = this._evaluateStructure(style);
 
     // In case the next call to render() is not preceded by a call to shouldUpdate(), force the next
     // render() call to re-evaluate variables.
@@ -151,11 +151,9 @@ export class ConfigTemplateCard extends LitElement {
     element.hass = this.hass;
 
     if (this._config.element) {
-      if (style) {
-        Object.keys(style).forEach((prop) => {
-          this.style.setProperty(prop, style[prop]);
-        });
-      }
+      Object.keys(style).forEach((prop) => {
+        this.style.setProperty(prop, style[prop]);
+      });
       if (configSection?.style) {
         Object.keys(configSection.style).forEach((prop) => {
           if (configSection.style) {  // TypeScript requires a redundant check here, not sure why
@@ -186,6 +184,7 @@ export class ConfigTemplateCard extends LitElement {
         struct[i] = this._evaluateStructure(value);
       }
     } else if (typeof struct === 'object') {
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
       Object.entries(struct).forEach(entry => {
         const key = entry[0];
         const value = entry[1];
@@ -204,8 +203,8 @@ export class ConfigTemplateCard extends LitElement {
       return this._evalWithVars(template.substring(2, template.length - 1));
     }
 
-    template.match(/\${[^}]+}/)?.forEach(m => {
-      const repl = this._evalWithVars(m.substring(2, m.length - 1));
+    /\${[^}]+}/.exec(template)?.forEach(m => {
+      const repl = this._evalWithVars(m.substring(2, m.length - 1)).toString() as string;
       template = template.replace(m, repl);
     });
     return template;
@@ -227,6 +226,7 @@ export class ConfigTemplateCard extends LitElement {
 
     if (this._config?.variables) {
       if (Array.isArray(this._config.variables)) {
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
         arrayVars.push(...this._config.variables);
       } else {
         Object.assign(namedVars, this._config.variables);
@@ -236,14 +236,14 @@ export class ConfigTemplateCard extends LitElement {
     const localVars = this.getLovelaceConfig();
     if (localVars) {
       if (Array.isArray(localVars)) {
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
         arrayVars.push(...localVars);
       } else {
         Object.assign(namedVars, localVars);
       }
     }
 
-    for (const idx in arrayVars) {
-      let v = arrayVars[idx];
+    for (let v of arrayVars) {
       if (isString(v)) { v = this._evalWithVars(v); }
       else { v = structuredClone(v); }
       vars.push(v);
diff --git a/src/types.ts b/src/types.ts
index a8c4482..a2d9d88 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -8,7 +8,7 @@ interface StyleMixin {
 
 export interface ConfigTemplateConfig {
   type: string;
-  entities: string[];
+  entities?: string[];
   variables?: Record<string, any> | any[];
   card?: LovelaceCardConfig & StyleMixin;
   row?: EntitiesCardEntityConfig & StyleMixin;
diff --git a/tsconfig.json b/tsconfig.json
index 20ef36b..159a683 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,18 +2,24 @@
   "compilerOptions": {
     "target": "es2017",
     "module": "esnext",
-    "moduleResolution": "node",
+    "moduleResolution": "bundler",
     "lib": [
       "es2017",
       "dom",
       "dom.iterable"
     ],
-    "noEmit": true,
+
+    "noEmit": false,
     "sourceMap": true,
+    "declaration": false,
+    "declarationMap": false,
+    "tsBuildInfoFile": ".tsbuildinfo",
+
+    "noCheck": false,
+    "strict": true,
     "noUnusedParameters": true,
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
-    "strict": true,
     "noImplicitAny": false,
     "skipLibCheck": true,
     "resolveJsonModule": true,