refactor: fetch処理を関数で切り出して、1関数あたりの認知複雑度を改善

islands/ImageForm.tsx

@@ -1,5 +1,20 @@
 import { useSignal } from "https://esm.sh/*@preact/signals@1.2.1";
 
+const createAsciiArt = async (image: File) => {
+ const formData = new FormData();
+ formData.append("files", image);
+ const url =
+ location.hostname === "localhost"
+ ? "http://127.0.0.1:8080/files/"
+ : "https://create-ascii-art.onrender.com/files/";
+ const response = await fetch(url, {
+ method: "POST",
+ body: formData,
+ mode: "cors",
+ });
+ return response.blob();
+};
+
 export default function ImageForm() {
  const isActiveFileUpLoderDisable = useSignal(false);
  const buttonDisable = useSignal(false);
@@ -35,18 +50,7 @@ export default function ImageForm() {
  previewUploadImage.value = true;
  isAnnounsing.value = true;
 
- const formData = new FormData();
- formData.append("files", image);
- const url =
- location.hostname === "localhost"
- ? "http://127.0.0.1:8080/files/"
- : "https://create-ascii-art.onrender.com/files/";
- const response = await fetch(url, {
- method: "POST",
- body: formData,
- mode: "cors",
- });
- const asciiArtBlob = await response.blob();
+ const asciiArtBlob = await createAsciiArt(image);
  const blobUrl = await window.URL.createObjectURL(asciiArtBlob);
  const fileData = new FileReader();
  fileData.onload = () => {