transition from javascript to typescript

assets/ts/main.ts

@@ -0,0 +1,13 @@
+import { footerHeightUpdateInit } from './utils'
+import { imgIndexSpanUpdate } from './indexDisp'
+import { imagesArrayLen, trackMouseInit } from './trackMouse'
+import { thresholdCtlInit } from './thresholdCtl'
+
+function init(): void {
+  footerHeightUpdateInit()
+  imgIndexSpanUpdate(0, imagesArrayLen)
+  thresholdCtlInit()
+  trackMouseInit()
+}
+
+init()