Fix uploader not reading multiple property from the input element pro…

…perly, closes #7276

packages/corelib/src/base/uploader.spec.tsx

@@ -0,0 +1,11 @@
+import { Uploader } from "./uploader";
+
+describe("Uploader", () => {
+    it("reads multiple from the input if not passed via options", () => {
+        const input = <input multiple={true} /> as HTMLInputElement;
+        const uploader = new Uploader({ 
+            input
+        });
+        expect(uploader["isMultiple"]?.()).toBe(true);
+    });
+});

packages/corelib/src/base/uploader.ts

@@ -150,7 +150,7 @@ export class Uploader {
     }
 
     private isMultiple() {
-        return !!(this.opt.multiple ?? this.opt?.input?.getAttribute("multiple"));
+        return !!(this.opt.multiple ?? (this.opt?.input as HTMLInputElement)?.multiple);
     }
 
     private getTypePredicate(): ((type: string) => boolean) {

packages/corelib/src/ui/helpers/uploadhelper.spec.tsx

@@ -0,0 +1,13 @@
+import { UploadHelper } from "./uploadhelper";
+
+describe("UploadHelper.addUploadInput", () => {
+    it("should set inputs multiple attribute to true if options.allowMultiple is true", () => {
+        const container = document.body.appendChild(<div/>) as HTMLElement;
+        const input = UploadHelper.addUploadInput({
+            container,
+            inputName: "file",
+            allowMultiple: true
+        });
+        expect((input.getNode() as HTMLInputElement).multiple).toBe(true);
+    });
+});

packages/corelib/src/ui/helpers/uploadhelper.tsx

@@ -27,7 +27,7 @@ export namespace UploadHelper {
             bar && (bar.style.width = (percent ?? 0).toString() + '%');
         }
 
-        new Uploader({
+        var uploader = new Uploader({
             batchSize: 1,
             batchSuccess: data => {
                 const response: UploadResponse = data.response ?? {};
@@ -57,6 +57,8 @@ export namespace UploadHelper {
             }
         });
 
+        uploadInput.getNode()?.uploader = uploader;
+
         return uploadInput;
     }