diff --git a/src/rendering/cache/bitmap-cache.ts b/src/rendering/cache/bitmap-cache.ts
index 9c96d51..906c3c6 100644
--- a/src/rendering/cache/bitmap-cache.ts
+++ b/src/rendering/cache/bitmap-cache.ts
@@ -20,13 +20,20 @@
  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-import type { Layer } from "@/definitions/document";
+import type { Layer, Filters, Text } from "@/definitions/document";
 
-const layerCache: Map<string, any> = new Map();
+export type RenderCache = {
+    text?: Text;
+    textBitmap?: HTMLCanvasElement;
+    filters?: Filters;
+    filterData?: ImageData;
+};
 
-export const getLayerCache = ( layer: Layer ): any => layerCache.get( layer.id );
+const layerCache: Map<string, RenderCache> = new Map();
 
-export const setLayerCache = ( layer: Layer, props: any ): void => {
+export const getLayerCache = ( layer: Layer ): RenderCache => layerCache.get( layer.id );
+
+export const setLayerCache = ( layer: Layer, props: RenderCache ): void => {
     const cache = getLayerCache( layer ) ?? {};
     layerCache.set( layer.id, { ...cache, ...props });
 };
@@ -35,7 +42,9 @@ export const hasLayerCache = ( layer: Layer ): boolean => layerCache.has( layer.
 
 export const clearCacheProperty = ( layer: Layer, propertyName: string ): void => {
     const cache = getLayerCache( layer );
+    // @ts-expect-error using string as key
     if ( cache?.[ propertyName ] ) {
+        // @ts-expect-error using string as key
         delete cache[ propertyName ];
     }
 };
diff --git a/src/services/render-service.ts b/src/services/render-service.ts
index 53ef84c..0776d62 100644
--- a/src/services/render-service.ts
+++ b/src/services/render-service.ts
@@ -21,7 +21,7 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 import Vue from "vue";
-import type { Layer, Filters, Text } from "@/definitions/document";
+import type { Layer } from "@/definitions/document";
 import { LayerTypes } from "@/definitions/layer-types";
 import { getSpriteForLayer } from "@/factories/sprite-factory";
 import { hasFilters, isEqual as isFiltersEqual } from "@/factories/filters-factory";
@@ -29,6 +29,7 @@ import { isEqual as isTextEqual } from "@/factories/text-factory";
 import { createCanvas, cloneCanvas, matchDimensions } from "@/utils/canvas-util";
 import { replaceLayerSource } from "@/utils/layer-util";
 import { getLayerCache, setLayerCache } from "@/rendering/cache/bitmap-cache";
+import type { RenderCache } from "@/rendering/cache/bitmap-cache";
 import { renderMultiLineText } from "@/rendering/text";
 import { loadGoogleFont } from "@/services/font-service";
 import FilterWorker from "@/workers/filter.worker?worker";
@@ -40,13 +41,6 @@ type RenderJob = {
     error: ( error?: any ) => void;
 };
 
-type RenderCache = {
-    text?: Text;
-    textBitmap?: HTMLCanvasElement;
-    filters?: Filters;
-    filterData?: ImageData;
-};
-
 const jobQueue: RenderJob[] = [];
 let UID = 0;
 
diff --git a/tests/unit/definitions/file-types.spec.js b/tests/unit/definitions/file-types.spec.ts
similarity index 100%
rename from tests/unit/definitions/file-types.spec.js
rename to tests/unit/definitions/file-types.spec.ts
diff --git a/tests/unit/definitions/image-types.spec.js b/tests/unit/definitions/image-types.spec.ts
similarity index 100%
rename from tests/unit/definitions/image-types.spec.js
rename to tests/unit/definitions/image-types.spec.ts
diff --git a/tests/unit/factories/brush-factory.spec.js b/tests/unit/factories/brush-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/brush-factory.spec.js
rename to tests/unit/factories/brush-factory.spec.ts
diff --git a/tests/unit/factories/document-factory.spec.js b/tests/unit/factories/document-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/document-factory.spec.js
rename to tests/unit/factories/document-factory.spec.ts
diff --git a/tests/unit/factories/effects-factory.spec.js b/tests/unit/factories/effects-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/effects-factory.spec.js
rename to tests/unit/factories/effects-factory.spec.ts
diff --git a/tests/unit/factories/filters-factory.spec.js b/tests/unit/factories/filters-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/filters-factory.spec.js
rename to tests/unit/factories/filters-factory.spec.ts
diff --git a/tests/unit/factories/history-state-factory.spec.js b/tests/unit/factories/history-state-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/history-state-factory.spec.js
rename to tests/unit/factories/history-state-factory.spec.ts
diff --git a/tests/unit/factories/layer-factory.spec.js b/tests/unit/factories/layer-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/layer-factory.spec.js
rename to tests/unit/factories/layer-factory.spec.ts
diff --git a/tests/unit/factories/sprite-factory.spec.js b/tests/unit/factories/sprite-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/sprite-factory.spec.js
rename to tests/unit/factories/sprite-factory.spec.ts
diff --git a/tests/unit/factories/text-factory.spec.js b/tests/unit/factories/text-factory.spec.ts
similarity index 100%
rename from tests/unit/factories/text-factory.spec.js
rename to tests/unit/factories/text-factory.spec.ts
diff --git a/tests/unit/math/image-math.spec.js b/tests/unit/math/image-math.spec.ts
similarity index 100%
rename from tests/unit/math/image-math.spec.js
rename to tests/unit/math/image-math.spec.ts
diff --git a/tests/unit/math/point-math.spec.js b/tests/unit/math/point-math.spec.ts
similarity index 100%
rename from tests/unit/math/point-math.spec.js
rename to tests/unit/math/point-math.spec.ts
diff --git a/tests/unit/math/rectangle-math.spec.js b/tests/unit/math/rectangle-math.spec.ts
similarity index 100%
rename from tests/unit/math/rectangle-math.spec.js
rename to tests/unit/math/rectangle-math.spec.ts
diff --git a/tests/unit/math/selection-math.spec.js b/tests/unit/math/selection-math.spec.ts
similarity index 100%
rename from tests/unit/math/selection-math.spec.js
rename to tests/unit/math/selection-math.spec.ts
diff --git a/tests/unit/math/unit-math.spec.js b/tests/unit/math/unit-math.spec.ts
similarity index 100%
rename from tests/unit/math/unit-math.spec.js
rename to tests/unit/math/unit-math.spec.ts
diff --git a/tests/unit/rendering/cache/bitmap-cache.spec.js b/tests/unit/rendering/cache/bitmap-cache.spec.ts
similarity index 100%
rename from tests/unit/rendering/cache/bitmap-cache.spec.js
rename to tests/unit/rendering/cache/bitmap-cache.spec.ts
diff --git a/tests/unit/store/modules/canvas-module.spec.js b/tests/unit/store/modules/canvas-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/canvas-module.spec.js
rename to tests/unit/store/modules/canvas-module.spec.ts
diff --git a/tests/unit/store/modules/document-module.spec.js b/tests/unit/store/modules/document-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/document-module.spec.js
rename to tests/unit/store/modules/document-module.spec.ts
diff --git a/tests/unit/store/modules/history-module.spec.js b/tests/unit/store/modules/history-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/history-module.spec.js
rename to tests/unit/store/modules/history-module.spec.ts
diff --git a/tests/unit/store/modules/image-module.spec.js b/tests/unit/store/modules/image-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/image-module.spec.js
rename to tests/unit/store/modules/image-module.spec.ts
diff --git a/tests/unit/store/modules/preferences-module.spec.js b/tests/unit/store/modules/preferences-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/preferences-module.spec.js
rename to tests/unit/store/modules/preferences-module.spec.ts
diff --git a/tests/unit/store/modules/tool-module.spec.js b/tests/unit/store/modules/tool-module.spec.ts
similarity index 100%
rename from tests/unit/store/modules/tool-module.spec.js
rename to tests/unit/store/modules/tool-module.spec.ts
diff --git a/tests/unit/store/store.spec.js b/tests/unit/store/store.spec.ts
similarity index 100%
rename from tests/unit/store/store.spec.js
rename to tests/unit/store/store.spec.ts
diff --git a/tests/unit/utils/document-util.spec.js b/tests/unit/utils/document-util.spec.ts
similarity index 100%
rename from tests/unit/utils/document-util.spec.js
rename to tests/unit/utils/document-util.spec.ts
diff --git a/tsconfig.app.json b/tsconfig.app.json
index 5fe0f43..63f1901 100644
--- a/tsconfig.app.json
+++ b/tsconfig.app.json
@@ -11,7 +11,7 @@
         "noImplicitAny": true,
         "removeComments": true,
         "paths": {
-            "@/*": [ "./src/*" ]
+            "@/*": [ "./src/*", "./tests/*" ]
         }
     },
     "exclude": [
diff --git a/tsconfig.check.json b/tsconfig.check.json
index e129b63..c49b1d7 100644
--- a/tsconfig.check.json
+++ b/tsconfig.check.json
@@ -1,6 +1,6 @@
 {
     "extends": "./tsconfig.app.json",
-    "includes": [ "src/**/*.ts" ],
+    "includes": [ "src/**/*.ts", "tests/**/*.ts" ],
     "compilerOptions": {
         "skipLibCheck": true
     }