fix: prevent possible race condition on upload flows/folders (#4114)

* ✨ (create-file-upload.ts): improve file upload functionality by adding cleanup logic and handling edge cases for resolving file selection

* 🐛 (create-file-upload.ts): fix removing input element from the DOM by checking if it is contained in the document body before removal
💡 (create-file-upload.ts): add a comment to clarify the purpose of the setTimeout function for a fallback timeout of 1 minute

* ✨ (create-file-upload.ts): change createFileUpload function to be asynchronous to support Promise return type for better handling of file upload operations

* 📝 (create-file-upload.ts): improve error handling when removing input element from the DOM
📝 (create-file-upload.ts): remove unnecessary comment about timeout value in the code

src/frontend/src/helpers/create-file-upload.ts

@@ -2,34 +2,59 @@ export async function createFileUpload(props?: {
   accept?: string;
   multiple?: boolean;
 }): Promise<File[]> {
-  let lock = false;
   return new Promise((resolve) => {
     const input = document.createElement("input");
     input.type = "file";
     input.accept = props?.accept ?? ".json";
     input.multiple = props?.multiple ?? true;
     input.style.display = "none";
-    // add a change event listener to the file input
+
-    input.onchange = async (e: Event) => {
+    let isResolved = false;
-      lock = true;
+
-      resolve(Array.from((e.target as HTMLInputElement).files!));
+    const cleanup = () => {
+      // Check if the input element still exists in the DOM before attempting to remove it
+      if (input && document.body.contains(input)) {
+        try {
           document.body.removeChild(input);
+        } catch (error) {
+          console.warn("Error removing input element:", error);
+        }
+      }
+      window.removeEventListener("focus", handleFocus);
     };
-    window.addEventListener(
+
-      "focus",
+    const handleChange = (e: Event) => {
-      () => {
+      if (!isResolved) {
+        isResolved = true;
+        const files = Array.from((e.target as HTMLInputElement).files!);
+        cleanup();
+        resolve(files);
+      }
+    };
+
+    const handleFocus = () => {
       setTimeout(() => {
-          if (!lock) {
+        if (!isResolved) {
+          isResolved = true;
+          cleanup();
           resolve([]);
-            document.body.removeChild(input);
         }
       }, 300);
-      },
+    };
-      { once: true },
+
-    );
+    input.addEventListener("change", handleChange);
-    // add the input element to the body to ensure it is part of the DOM
+    window.addEventListener("focus", handleFocus);
+
     document.body.appendChild(input);
-    // trigger the file input click event to open the file dialog
     input.click();
+
+    // Fallback timeout to ensure resolution
+    setTimeout(() => {
+      if (!isResolved) {
+        isResolved = true;
+        cleanup();
+        resolve([]);
+      }
+    }, 60000);
   });
 }