Fix beforeUpload will stop uploading when return (#7870)

value is undefined

it should be same as rc-upload

components/upload/Upload.tsx

@@ -223,13 +223,13 @@ export default class Upload extends React.Component<UploadProps, any> {
       return true;
     }
     const result = this.props.beforeUpload(file, fileList);
-    if (!result) {
+    if (result === false) {
       this.onChange({
         file,
         fileList,
       });
       return false;
-    } else if ((result as PromiseLike<any>).then) {
+    } else if (result && (result as PromiseLike<any>).then) {
       return result;
     }
     return true;

components/upload/__tests__/upload.test.js

@@ -53,4 +53,58 @@ describe('Upload', () => {
       },
     });
   });
+
+  it('should not stop upload when return value of beforeUpload is not false', (done) => {
+    const data = jest.fn();
+    const props = {
+      action: 'http://upload.com',
+      beforeUpload: () => false,
+      data,
+      onChange: () => {
+        expect(data).not.toBeCalled();
+        done();
+      },
+    };
+
+    const wrapper = mount(
+      <Upload {...props}>
+        <button>upload</button>
+      </Upload>
+    );
+
+    wrapper.find('input').simulate('change', {
+      target: {
+        files: [
+          { filename: 'foo.png' },
+        ],
+      },
+    });
+  });
+
+  it('should not stop upload when return value of beforeUpload is not false', (done) => {
+    const data = jest.fn();
+    const props = {
+      action: 'http://upload.com',
+      beforeUpload() {},
+      data,
+      onChange: () => {
+        expect(data).toBeCalled();
+        done();
+      },
+    };
+
+    const wrapper = mount(
+      <Upload {...props}>
+        <button>upload</button>
+      </Upload>
+    );
+
+    wrapper.find('input').simulate('change', {
+      target: {
+        files: [
+          { filename: 'foo.png' },
+        ],
+      },
+    });
+  });
 });