diff --git a/types/prosemirror-model/index.d.ts b/types/prosemirror-model/index.d.ts
index f3e7675807..91852a4c65 100644
--- a/types/prosemirror-model/index.d.ts
+++ b/types/prosemirror-model/index.d.ts
@@ -1390,7 +1390,7 @@ export class Schema<N extends string = any, M extends string = any> {
 }
 export interface DOMOutputSpecArray {
   0: string;
-  1?: DOMOutputSpec | 0 | { [attr: string]: string };
+  1?: DOMOutputSpec | 0 | { [attr: string]: string | null | undefined };
   2?: DOMOutputSpec | 0;
   3?: DOMOutputSpec | 0;
   4?: DOMOutputSpec | 0;
diff --git a/types/prosemirror-model/prosemirror-model-tests.ts b/types/prosemirror-model/prosemirror-model-tests.ts
index b9041597e7..280a36667e 100644
--- a/types/prosemirror-model/prosemirror-model-tests.ts
+++ b/types/prosemirror-model/prosemirror-model-tests.ts
@@ -7,6 +7,8 @@ let domOutputSpec: model.DOMOutputSpec;
 domOutputSpec = ['div'];
 domOutputSpec = ['div', { class: 'foo' }];
 domOutputSpec = ['div', { class: 'foo' }, 0];
+domOutputSpec = ['div', { class: null }];
+domOutputSpec = ['div', { class: undefined }];
 domOutputSpec = ['div', 0];
 domOutputSpec = ['div', ['div', 0]];
 domOutputSpec = ['div', ['div', { class: 'foo' }]];