diff --git a/renderers/web_core/src/v0_8/types/types.ts b/renderers/web_core/src/v0_8/types/types.ts
index 1e1f6686..d6cdb46f 100644
--- a/renderers/web_core/src/v0_8/types/types.ts
+++ b/renderers/web_core/src/v0_8/types/types.ts
@@ -312,7 +312,7 @@ export type ResolvedValue =
   | ResolvedArray;
 
 /** A generic map where each value has been recursively resolved. */
-export type ResolvedMap = { [key: string]: ResolvedValue };
+export type ResolvedMap = { [key: string]?: ResolvedValue };
 
 /** A generic array where each item has been recursively resolved. */
 export type ResolvedArray = ResolvedValue[];