diff --git a/packages/mermaid/src/config.ts b/packages/mermaid/src/config.ts
index 31f0592de9..9468a3e461 100644
--- a/packages/mermaid/src/config.ts
+++ b/packages/mermaid/src/config.ts
@@ -230,7 +230,7 @@ const ConfigWarning = {
 } as const;
 
 type ConfigWarningStrings = keyof typeof ConfigWarning;
-const issuedWarnings: { [key in ConfigWarningStrings]?: boolean } = {};
+const issuedWarnings: Partial<Record<ConfigWarningStrings, boolean>> = {};
 const issueWarning = (warning: ConfigWarningStrings) => {
   if (issuedWarnings[warning]) {
     return;
diff --git a/packages/mermaid/src/diagrams/architecture/architectureTypes.ts b/packages/mermaid/src/diagrams/architecture/architectureTypes.ts
index b3ef55ec69..2ae000f697 100644
--- a/packages/mermaid/src/diagrams/architecture/architectureTypes.ts
+++ b/packages/mermaid/src/diagrams/architecture/architectureTypes.ts
@@ -104,9 +104,7 @@ export const isValidArchitectureDirectionPair = function (
   return x !== 'LL' && x !== 'RR' && x !== 'TT' && x !== 'BB';
 };
 
-export type ArchitectureDirectionPairMap = {
-  [key in ArchitectureDirectionPair]?: string;
-};
+export type ArchitectureDirectionPairMap = Partial<Record<ArchitectureDirectionPair, string>>;
 
 /**
  * Creates a pair of the directions of each side of an edge. This function should be used instead of manually creating it to ensure that the source is always the first character.