diff --git a/assets/ts/dataFetch.ts b/assets/ts/dataFetch.ts
index 81adbc7..07db65d 100644
--- a/assets/ts/dataFetch.ts
+++ b/assets/ts/dataFetch.ts
@@ -1,9 +1,4 @@
-interface ImageData {
-  index: string
-  url: string
-  imgH: string
-  imgW: string
-}
+import { type ImageData } from './utils'
 
 // fetch images info from JSON
 const imageArrayElement = document.getElementById('images_array') as HTMLScriptElement
diff --git a/assets/ts/trackMouse.ts b/assets/ts/trackMouse.ts
index 78dfecc..8ecb46d 100644
--- a/assets/ts/trackMouse.ts
+++ b/assets/ts/trackMouse.ts
@@ -1,14 +1,9 @@
 import { overlayEnable } from './overlay'
-import { posCache, FIFO, layersPosSet, center } from './utils'
+import { posCache, FIFO, layersPosSet, center, type position } from './utils'
 import { thresholdSensitivityArray, thresholdIndex } from './thresholdCtl'
 import { imgIndexSpanUpdate } from './indexDisp'
 import { imagesArrayLen, imagesArray } from './dataFetch'
 
-export interface position {
-  x: number
-  y: number
-}
-
 // get layer divs
 const layer5 = document.getElementById('layer5') as HTMLDivElement
 const layer4 = document.getElementById('layer4') as HTMLDivElement
diff --git a/assets/ts/utils.ts b/assets/ts/utils.ts
index 3b17e6e..a9d865a 100644
--- a/assets/ts/utils.ts
+++ b/assets/ts/utils.ts
@@ -1,3 +1,15 @@
+export interface ImageData {
+  index: string
+  url: string
+  imgH: string
+  imgW: string
+}
+
+export interface position {
+  x: number
+  y: number
+}
+
 // cache a xy position to array
 export const posCache = (x: number, y: number, xyArray: string[][]): void => {
   // pop element if length surpass limitation