new web init

web_app/src/hooks/useImage.tsx

@@ -0,0 +1,24 @@
+import { useEffect, useState } from "react"
+
+function useImage(file?: File): [HTMLImageElement, boolean] {
+  const [image] = useState(new Image())
+  const [isLoaded, setIsLoaded] = useState(false)
+
+  useEffect(() => {
+    if (file === undefined) {
+      return
+    }
+    image.onload = () => {
+      setIsLoaded(true)
+    }
+    setIsLoaded(false)
+    image.src = URL.createObjectURL(file)
+    return () => {
+      image.onload = null
+    }
+  }, [file, image])
+
+  return [image, isLoaded]
+}
+
+export { useImage }