fix(appsync): Not to throw an Error even if 'additionalAuthorizationM…

…odes' is undefined

fixes #8666 #8668

packages/@aws-cdk/aws-appsync/lib/graphqlapi.ts

@@ -335,12 +335,7 @@ export class GraphQLApi extends Construct {
             props.authorizationConfig.defaultAuthorization.userPoolConfig!,
           )
           : undefined,
-      additionalAuthenticationProviders: props.authorizationConfig
-        ?.additionalAuthorizationModes!.length
-        ? this.formatAdditionalAuthorizationModes(
-          props.authorizationConfig!.additionalAuthorizationModes!,
-        )
-        : undefined,
+      additionalAuthenticationProviders: this.formatAdditionalAuthenticationProviders(props),
     });
 
     this.apiId = this.api.attrApiId;
@@ -569,6 +564,11 @@ export class GraphQLApi extends Construct {
       [],
     );
   }
+
+  private formatAdditionalAuthenticationProviders(props: GraphQLApiProps): CfnGraphQLApi.AdditionalAuthenticationProviderProperty[] | undefined {
+    const authModes = props.authorizationConfig?.additionalAuthorizationModes;
+    return authModes ? this.formatAdditionalAuthorizationModes(authModes) : undefined;
+  }
 }
 
 /**

packages/@aws-cdk/aws-appsync/test/appsync.test.ts

@@ -1,6 +1,21 @@
 import '@aws-cdk/assert/jest';
-import {} from '../lib';
+import * as cdk from '@aws-cdk/core';
+import * as path from 'path';
+import * as appsync from '../lib';
 
-test('No tests are specified for this package', () => {
-  expect(true).toBe(true);
+test('should not throw an Error', () => {
+  // Given
+  const stack = new cdk.Stack();
+
+  // When
+  const when = () => {
+    new appsync.GraphQLApi(stack, 'api', {
+      authorizationConfig: {},
+      name: 'api',
+      schemaDefinitionFile: path.join(__dirname, 'schema.graphql'),
+    });
+  };
+
+  // Then
+  expect(when).not.toThrow();
 });