chore: add base64ToFile

Author: Simon he

src/base64ToFile.ts

@@ -0,0 +1,11 @@
+export function base64ToFile(s: string, filename: string): File {
+  const arr = s.split(','),
+    mime = arr[0]?.match(/:(.*?);/)?.[1],
+    bstr = atob(arr[1])
+  let n = bstr.length
+  const u8arr = new Uint8Array(n);
+  while (n--) {
+    u8arr[n] = bstr.charCodeAt(n);
+  }
+  return new File([u8arr], filename, { type: mime });
+}