fix: handle getFile returning null and close #106

src/file-selector.spec.ts

@@ -333,6 +333,35 @@ it('should not use getAsFileSystemHandle when not in a secure context', async ()
     window.isSecureContext = true;
 });
 
+it('should reject when getAsFileSystemHandle resolves to null', async () => {
+    const evt = dragEvtFromItems([
+        dataTransferItemWithFsHandle(null, null)
+    ]);
+    expect(fromEvent(evt)).rejects.toThrow('[object Object] is not a File');
+});
+
+it('should fallback to getAsFile when getAsFileSystemHandle resolves to undefined', async () => {
+    const name = 'test.nosec.json';
+    const mockFile = createFile(name, {ping: false}, {
+        type: 'application/json'
+    });
+    const evt = dragEvtFromItems([
+        dataTransferItemWithFsHandle(mockFile, undefined)
+    ]);
+
+    const files = await fromEvent(evt);
+    expect(files).toHaveLength(1);
+    expect(files.every(file => file instanceof File)).toBe(true);
+
+    const [file] = files as FileWithPath[];
+
+    expect(file.name).toBe(mockFile.name);
+    expect(file.type).toBe(mockFile.type);
+    expect(file.size).toBe(mockFile.size);
+    expect(file.lastModified).toBe(mockFile.lastModified);
+    expect(file.path).toBe(`./${name}`);
+});
+
 function dragEvtFromItems(items: DataTransferItem | DataTransferItem[], type: string = 'drop'): DragEvent {
     return {
         type,
@@ -403,7 +432,7 @@ function dataTransferItemFromEntry(entry: FileEntry | DirEntry, file?: File): Da
     } as any;
 }
 
-function dataTransferItemWithFsHandle(file?: File, h?: FileSystemFileHandle): DataTransferItem {
+function dataTransferItemWithFsHandle(file?: File | null, h?: FileSystemFileHandle | null): DataTransferItem {
     return {
         kind: 'file',
         getAsFile() {
@@ -510,7 +539,7 @@ function sortFiles<T extends File>(files: T[]) {
 
 
 interface FileSystemFileHandle {
-    getFile(): Promise<File>;
+    getFile(): Promise<File | null>;
 }
 
 type FileOrDirEntry = FileEntry | DirEntry

src/file-selector.ts

@@ -120,27 +120,32 @@ function flatten<T>(items: any[]): T[] {
     ], []);
 }
 
-function fromDataTransferItem(item: DataTransferItem, entry?: FileSystemEntry | null) {
+async function fromDataTransferItem(item: DataTransferItem, entry?: FileSystemEntry | null) {
     // Check if we're in a secure context; due to a bug in Chrome (as far as we know)
     // the browser crashes when calling this API (yet to be confirmed as a consistent behaviour).
     //
     // See:
     // - https://issues.chromium.org/issues/40186242
     // - https://github.com/react-dropzone/react-dropzone/issues/1397
     if (globalThis.isSecureContext && typeof (item as any).getAsFileSystemHandle === 'function') {
-        return (item as any).getAsFileSystemHandle()
-            .then(async (h: any) => {
-                const file = await h.getFile();
-                file.handle = h;
-                return toFileWithPath(file);
-            });
+        const h = await (item as any).getAsFileSystemHandle();
+        if (h === null) {
+            throw new Error(`${item} is not a File`);
+        }
+        // It seems that the handle can be `undefined` (see https://github.com/react-dropzone/file-selector/issues/120),
+        // so we check if it isn't; if it is, the code path continues to the next API (`getAsFile`).
+        if (h !== undefined) {
+            const file = await h.getFile();
+            file.handle = h;
+            return toFileWithPath(file);
+        }
     }
     const file = item.getAsFile();
     if (!file) {
-        return Promise.reject(`${item} is not a File`);
+        throw new Error(`${item} is not a File`);
     }
     const fwp = toFileWithPath(file, entry?.fullPath ?? undefined);
-    return Promise.resolve(fwp);
+    return fwp;
 }
 
 // https://developer.mozilla.org/en-US/docs/Web/API/FileSystemEntry