diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index de2843bd2..e8dbf295e 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -1,4 +1,10 @@
 ### Improvements
+
+- [sdk/nodejs] - Type optional input properties as `Input<T | undefined> | undefined` instead of
+  `Input<T> | undefined`. This allows users to pass `Output<T | undefined>` for optional input
+  properties.
+  [#6323](https://github.com/pulumi/pulumi/pull/6323)
+
 - Adds CI detector for Buildkite
   [#7933](https://github.com/pulumi/pulumi/pull/7933)
 
diff --git a/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/submodule1/moduleResource.ts b/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/submodule1/moduleResource.ts
index 65b05b55d..3eddf5743 100644
--- a/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/submodule1/moduleResource.ts
+++ b/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/submodule1/moduleResource.ts
@@ -60,5 +60,5 @@ export class ModuleResource extends pulumi.CustomResource {
  * The set of arguments for constructing a ModuleResource resource.
  */
 export interface ModuleResourceArgs {
-    thing?: pulumi.Input<inputs.TopLevelArgs>;
+    thing?: pulumi.Input<inputs.TopLevelArgs | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/types/input.ts
index ab428c412..0dff351de 100644
--- a/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/dash-named-schema/nodejs/types/input.ts
@@ -5,5 +5,5 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs } from "../types";
 
 export interface TopLevelArgs {
-    buzz?: pulumi.Input<string>;
+    buzz?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/nursery.ts b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/nursery.ts
index d9d03bb54..0298f0aef 100644
--- a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/nursery.ts
+++ b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/nursery.ts
@@ -65,7 +65,7 @@ export interface NurseryArgs {
     /**
      * The sizes of trees available
      */
-    sizes?: pulumi.Input<{[key: string]: pulumi.Input<enums.tree.v1.TreeSize>}>;
+    sizes?: pulumi.Input<{[key: string]: pulumi.Input<enums.tree.v1.TreeSize>} | undefined>;
     /**
      * The varieties available
      */
diff --git a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/rubberTree.ts b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/rubberTree.ts
index bb0613bcd..5a10c99fb 100644
--- a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/rubberTree.ts
+++ b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/tree/v1/rubberTree.ts
@@ -75,16 +75,16 @@ export class RubberTree extends pulumi.CustomResource {
 }
 
 export interface RubberTreeState {
-    farm?: pulumi.Input<enums.tree.v1.Farm | string>;
+    farm?: pulumi.Input<enums.tree.v1.Farm | string | undefined>;
 }
 
 /**
  * The set of arguments for constructing a RubberTree resource.
  */
 export interface RubberTreeArgs {
-    container?: pulumi.Input<inputs.ContainerArgs>;
+    container?: pulumi.Input<inputs.ContainerArgs | undefined>;
     diameter: pulumi.Input<enums.tree.v1.Diameter>;
-    farm?: pulumi.Input<enums.tree.v1.Farm | string>;
-    size?: pulumi.Input<enums.tree.v1.TreeSize>;
+    farm?: pulumi.Input<enums.tree.v1.Farm | string | undefined>;
+    size?: pulumi.Input<enums.tree.v1.TreeSize | undefined>;
     type: pulumi.Input<enums.tree.v1.RubberTreeVariety>;
 }
diff --git a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/types/input.ts
index 52f85fdca..7def568b8 100644
--- a/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/dashed-import-schema/nodejs/types/input.ts
@@ -5,8 +5,8 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs, enums } from "../types";
 
 export interface ContainerArgs {
-    brightness?: pulumi.Input<enums.ContainerBrightness>;
-    color?: pulumi.Input<enums.ContainerColor | string>;
-    material?: pulumi.Input<string>;
+    brightness?: pulumi.Input<enums.ContainerBrightness | undefined>;
+    color?: pulumi.Input<enums.ContainerColor | string | undefined>;
+    material?: pulumi.Input<string | undefined>;
     size: pulumi.Input<enums.ContainerSize>;
 }
diff --git a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/argFunction.ts b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/argFunction.ts
index f92da28ee..ed2494259 100644
--- a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/argFunction.ts
+++ b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/argFunction.ts
@@ -33,5 +33,5 @@ export function argFunctionOutput(args?: ArgFunctionOutputArgs, opts?: pulumi.In
 }
 
 export interface ArgFunctionOutputArgs {
-    name?: pulumi.Input<pulumiRandom.RandomPet>;
+    name?: pulumi.Input<pulumiRandom.RandomPet | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/cat.ts b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/cat.ts
index f4aaf5b26..73f2c6964 100644
--- a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/cat.ts
+++ b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/cat.ts
@@ -64,6 +64,6 @@ export class Cat extends pulumi.CustomResource {
  * The set of arguments for constructing a Cat resource.
  */
 export interface CatArgs {
-    age?: pulumi.Input<number>;
-    pet?: pulumi.Input<inputs.PetArgs>;
+    age?: pulumi.Input<number | undefined>;
+    pet?: pulumi.Input<inputs.PetArgs | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/component.ts b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/component.ts
index 0be0b56f4..19dbaadf4 100644
--- a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/component.ts
+++ b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/component.ts
@@ -83,9 +83,9 @@ export class Component extends pulumi.CustomResource {
  * The set of arguments for constructing a Component resource.
  */
 export interface ComponentArgs {
-    metadata?: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>;
-    metadataArray?: pulumi.Input<pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>[]>;
-    metadataMap?: pulumi.Input<{[key: string]: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>}>;
+    metadata?: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs | undefined>;
+    metadataArray?: pulumi.Input<pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>[] | undefined>;
+    metadataMap?: pulumi.Input<{[key: string]: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>} | undefined>;
     requiredMetadata: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>;
     requiredMetadataArray: pulumi.Input<pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>[]>;
     requiredMetadataMap: pulumi.Input<{[key: string]: pulumi.Input<pulumiKubernetes.types.input.meta.v1.ObjectMetaArgs>}>;
diff --git a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/types/input.ts
index 07305e24c..a3a308aed 100644
--- a/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/external-resource-schema/nodejs/types/input.ts
@@ -7,10 +7,10 @@ import { input as inputs, output as outputs } from "../types";
 import * as pulumiRandom from "@pulumi/random";
 
 export interface PetArgs {
-    age?: pulumi.Input<number>;
-    name?: pulumi.Input<pulumiRandom.RandomPet>;
-    nameArray?: pulumi.Input<pulumi.Input<pulumiRandom.RandomPet>[]>;
-    nameMap?: pulumi.Input<{[key: string]: pulumi.Input<pulumiRandom.RandomPet>}>;
+    age?: pulumi.Input<number | undefined>;
+    name?: pulumi.Input<pulumiRandom.RandomPet | undefined>;
+    nameArray?: pulumi.Input<pulumi.Input<pulumiRandom.RandomPet>[] | undefined>;
+    nameMap?: pulumi.Input<{[key: string]: pulumi.Input<pulumiRandom.RandomPet>} | undefined>;
     requiredName: pulumi.Input<pulumiRandom.RandomPet>;
     requiredNameArray: pulumi.Input<pulumi.Input<pulumiRandom.RandomPet>[]>;
     requiredNameMap: pulumi.Input<{[key: string]: pulumi.Input<pulumiRandom.RandomPet>}>;
diff --git a/pkg/codegen/internal/test/testdata/nested-module-thirdparty/nodejs/deeply/nested/module/resource.ts b/pkg/codegen/internal/test/testdata/nested-module-thirdparty/nodejs/deeply/nested/module/resource.ts
index e15a4a59d..ed0a0f018 100644
--- a/pkg/codegen/internal/test/testdata/nested-module-thirdparty/nodejs/deeply/nested/module/resource.ts
+++ b/pkg/codegen/internal/test/testdata/nested-module-thirdparty/nodejs/deeply/nested/module/resource.ts
@@ -61,5 +61,5 @@ export class Resource extends pulumi.CustomResource {
  * The set of arguments for constructing a Resource resource.
  */
 export interface ResourceArgs {
-    baz?: pulumi.Input<string>;
+    baz?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/nested-module/nodejs/nested/module/resource.ts b/pkg/codegen/internal/test/testdata/nested-module/nodejs/nested/module/resource.ts
index b1a9f8fc7..19267c363 100644
--- a/pkg/codegen/internal/test/testdata/nested-module/nodejs/nested/module/resource.ts
+++ b/pkg/codegen/internal/test/testdata/nested-module/nodejs/nested/module/resource.ts
@@ -61,5 +61,5 @@ export class Resource extends pulumi.CustomResource {
  * The set of arguments for constructing a Resource resource.
  */
 export interface ResourceArgs {
-    bar?: pulumi.Input<string>;
+    bar?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listConfigurations.ts b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listConfigurations.ts
index e6435bccd..196989c04 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listConfigurations.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listConfigurations.ts
@@ -65,9 +65,9 @@ export interface ListConfigurationsOutputArgs {
     /**
      * Customer subscription properties. Clients can display available products to unregistered customers by explicitly passing subscription details
      */
-    customerSubscriptionDetails?: pulumi.Input<inputs.CustomerSubscriptionDetailsArgs>;
+    customerSubscriptionDetails?: pulumi.Input<inputs.CustomerSubscriptionDetailsArgs | undefined>;
     /**
      * $skipToken is supported on list of configurations, which provides the next page in the list of configurations.
      */
-    skipToken?: pulumi.Input<string>;
+    skipToken?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listProductFamilies.ts b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listProductFamilies.ts
index 08b91be4e..ca637a5a3 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listProductFamilies.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/listProductFamilies.ts
@@ -66,11 +66,11 @@ export interface ListProductFamiliesOutputArgs {
     /**
      * Customer subscription properties. Clients can display available products to unregistered customers by explicitly passing subscription details
      */
-    customerSubscriptionDetails?: pulumi.Input<inputs.CustomerSubscriptionDetailsArgs>;
+    customerSubscriptionDetails?: pulumi.Input<inputs.CustomerSubscriptionDetailsArgs | undefined>;
     /**
      * $expand is supported on configurations parameter for product, which provides details on the configurations for the product.
      */
-    expand?: pulumi.Input<string>;
+    expand?: pulumi.Input<string | undefined>;
     /**
      * Dictionary of filterable properties on product family.
      */
@@ -78,5 +78,5 @@ export interface ListProductFamiliesOutputArgs {
     /**
      * $skipToken is supported on list of product families, which provides the next page in the list of product families.
      */
-    skipToken?: pulumi.Input<string>;
+    skipToken?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/types/input.ts
index a53af10cb..0ff432f73 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs-edgeorder/nodejs/types/input.ts
@@ -11,7 +11,7 @@ export interface ConfigurationFiltersArgs {
     /**
      * Filters specific to product
      */
-    filterableProperty?: pulumi.Input<pulumi.Input<inputs.FilterablePropertyArgs>[]>;
+    filterableProperty?: pulumi.Input<pulumi.Input<inputs.FilterablePropertyArgs>[] | undefined>;
     /**
      * Product hierarchy information
      */
@@ -57,7 +57,7 @@ export interface CustomerSubscriptionDetailsArgs {
     /**
      * Location placement Id of a subscription
      */
-    locationPlacementId?: pulumi.Input<string>;
+    locationPlacementId?: pulumi.Input<string | undefined>;
     /**
      * Quota ID of a subscription
      */
@@ -65,7 +65,7 @@ export interface CustomerSubscriptionDetailsArgs {
     /**
      * List of registered feature flags for subscription
      */
-    registeredFeatures?: pulumi.Input<pulumi.Input<inputs.CustomerSubscriptionRegisteredFeaturesArgs>[]>;
+    registeredFeatures?: pulumi.Input<pulumi.Input<inputs.CustomerSubscriptionRegisteredFeaturesArgs>[] | undefined>;
 }
 
 /**
@@ -89,11 +89,11 @@ export interface CustomerSubscriptionRegisteredFeaturesArgs {
     /**
      * Name of subscription registered feature
      */
-    name?: pulumi.Input<string>;
+    name?: pulumi.Input<string | undefined>;
     /**
      * State of subscription registered feature
      */
-    state?: pulumi.Input<string>;
+    state?: pulumi.Input<string | undefined>;
 }
 
 /**
@@ -153,18 +153,18 @@ export interface HierarchyInformationArgs {
     /**
      * Represents configuration name that uniquely identifies configuration
      */
-    configurationName?: pulumi.Input<string>;
+    configurationName?: pulumi.Input<string | undefined>;
     /**
      * Represents product family name that uniquely identifies product family
      */
-    productFamilyName?: pulumi.Input<string>;
+    productFamilyName?: pulumi.Input<string | undefined>;
     /**
      * Represents product line name that uniquely identifies product line
      */
-    productLineName?: pulumi.Input<string>;
+    productLineName?: pulumi.Input<string | undefined>;
     /**
      * Represents product name that uniquely identifies product
      */
-    productName?: pulumi.Input<string>;
+    productName?: pulumi.Input<string | undefined>;
 }
 
diff --git a/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/getAmiIds.ts b/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/getAmiIds.ts
index 0957a0143..69c8f0f48 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/getAmiIds.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/getAmiIds.ts
@@ -88,13 +88,13 @@ export interface GetAmiIdsOutputArgs {
      * Limit search to users with *explicit* launch
      * permission on  the image. Valid items are the numeric account ID or `self`.
      */
-    executableUsers?: pulumi.Input<pulumi.Input<string>[]>;
+    executableUsers?: pulumi.Input<pulumi.Input<string>[] | undefined>;
     /**
      * One or more name/value pairs to filter off of. There
      * are several valid keys, for a full reference, check out
      * [describe-images in the AWS CLI reference][1].
      */
-    filters?: pulumi.Input<pulumi.Input<inputs.GetAmiIdsFilterArgs>[]>;
+    filters?: pulumi.Input<pulumi.Input<inputs.GetAmiIdsFilterArgs>[] | undefined>;
     /**
      * A regex string to apply to the AMI list returned
      * by AWS. This allows more advanced filtering not supported from the AWS API.
@@ -102,7 +102,7 @@ export interface GetAmiIdsOutputArgs {
      * impact if the result is large. It is recommended to combine this with other
      * options to narrow down the list AWS returns.
      */
-    nameRegex?: pulumi.Input<string>;
+    nameRegex?: pulumi.Input<string | undefined>;
     /**
      * List of AMI owners to limit search. At least 1 value must be specified. Valid values: an AWS account ID, `self` (the current account), or an AWS owner alias (e.g. `amazon`, `aws-marketplace`, `microsoft`).
      */
@@ -110,5 +110,5 @@ export interface GetAmiIdsOutputArgs {
     /**
      * Used to sort AMIs by creation time.
      */
-    sortAscending?: pulumi.Input<boolean>;
+    sortAscending?: pulumi.Input<boolean | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/listStorageAccountKeys.ts b/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/listStorageAccountKeys.ts
index 2ceef86a4..9f0f0d794 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/listStorageAccountKeys.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs-tfbridge20/nodejs/listStorageAccountKeys.ts
@@ -61,7 +61,7 @@ export interface ListStorageAccountKeysOutputArgs {
     /**
      * Specifies type of the key to be listed. Possible value is kerb.
      */
-    expand?: pulumi.Input<string>;
+    expand?: pulumi.Input<string | undefined>;
     /**
      * The name of the resource group within the user's subscription. The name is case insensitive.
      */
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithAllOptionalInputs.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithAllOptionalInputs.ts
index 37b7cac7e..7e60b20b4 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithAllOptionalInputs.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithAllOptionalInputs.ts
@@ -45,9 +45,9 @@ export interface FuncWithAllOptionalInputsOutputArgs {
     /**
      * Property A
      */
-    a?: pulumi.Input<string>;
+    a?: pulumi.Input<string | undefined>;
     /**
      * Property B
      */
-    b?: pulumi.Input<string>;
+    b?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDefaultValue.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDefaultValue.ts
index 116d3dddc..b968d3b1f 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDefaultValue.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDefaultValue.ts
@@ -36,5 +36,5 @@ export function funcWithDefaultValueOutput(args: FuncWithDefaultValueOutputArgs,
 
 export interface FuncWithDefaultValueOutputArgs {
     a: pulumi.Input<string>;
-    b?: pulumi.Input<string>;
+    b?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDictParam.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDictParam.ts
index fd53e3f2e..11ba8478a 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDictParam.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithDictParam.ts
@@ -36,6 +36,6 @@ export function funcWithDictParamOutput(args?: FuncWithDictParamOutputArgs, opts
 }
 
 export interface FuncWithDictParamOutputArgs {
-    a?: pulumi.Input<{[key: string]: pulumi.Input<string>}>;
-    b?: pulumi.Input<string>;
+    a?: pulumi.Input<{[key: string]: pulumi.Input<string>} | undefined>;
+    b?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithListParam.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithListParam.ts
index 27f32609d..db826e578 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithListParam.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/funcWithListParam.ts
@@ -36,6 +36,6 @@ export function funcWithListParamOutput(args?: FuncWithListParamOutputArgs, opts
 }
 
 export interface FuncWithListParamOutputArgs {
-    a?: pulumi.Input<pulumi.Input<string>[]>;
-    b?: pulumi.Input<string>;
+    a?: pulumi.Input<pulumi.Input<string>[] | undefined>;
+    b?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getBastionShareableLink.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getBastionShareableLink.ts
index 35aed8c80..0afbe00ab 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getBastionShareableLink.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getBastionShareableLink.ts
@@ -65,5 +65,5 @@ export interface GetBastionShareableLinkOutputArgs {
     /**
      * List of VM references.
      */
-    vms?: pulumi.Input<pulumi.Input<inputs.BastionShareableLinkArgs>[]>;
+    vms?: pulumi.Input<pulumi.Input<inputs.BastionShareableLinkArgs>[] | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getIntegrationRuntimeObjectMetadatum.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getIntegrationRuntimeObjectMetadatum.ts
index 6018b25ed..33a297f23 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getIntegrationRuntimeObjectMetadatum.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/getIntegrationRuntimeObjectMetadatum.ts
@@ -74,7 +74,7 @@ export interface GetIntegrationRuntimeObjectMetadatumOutputArgs {
     /**
      * Metadata path.
      */
-    metadataPath?: pulumi.Input<string>;
+    metadataPath?: pulumi.Input<string | undefined>;
     /**
      * The resource group name.
      */
diff --git a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/listStorageAccountKeys.ts b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/listStorageAccountKeys.ts
index 2ceef86a4..9f0f0d794 100644
--- a/pkg/codegen/internal/test/testdata/output-funcs/nodejs/listStorageAccountKeys.ts
+++ b/pkg/codegen/internal/test/testdata/output-funcs/nodejs/listStorageAccountKeys.ts
@@ -61,7 +61,7 @@ export interface ListStorageAccountKeysOutputArgs {
     /**
      * Specifies type of the key to be listed. Possible value is kerb.
      */
-    expand?: pulumi.Input<string>;
+    expand?: pulumi.Input<string | undefined>;
     /**
      * The name of the resource group within the user's subscription. The name is case insensitive.
      */
diff --git a/pkg/codegen/internal/test/testdata/plain-and-default/nodejs/moduleResource.ts b/pkg/codegen/internal/test/testdata/plain-and-default/nodejs/moduleResource.ts
index 191b59df3..c4f8a6e78 100644
--- a/pkg/codegen/internal/test/testdata/plain-and-default/nodejs/moduleResource.ts
+++ b/pkg/codegen/internal/test/testdata/plain-and-default/nodejs/moduleResource.ts
@@ -98,11 +98,11 @@ export class ModuleResource extends pulumi.CustomResource {
  * The set of arguments for constructing a ModuleResource resource.
  */
 export interface ModuleResourceArgs {
-    optional_bool?: pulumi.Input<boolean>;
-    optional_const?: pulumi.Input<"val">;
-    optional_enum?: pulumi.Input<enums.EnumThing>;
-    optional_number?: pulumi.Input<number>;
-    optional_string?: pulumi.Input<string>;
+    optional_bool?: pulumi.Input<boolean | undefined>;
+    optional_const?: pulumi.Input<"val" | undefined>;
+    optional_enum?: pulumi.Input<enums.EnumThing | undefined>;
+    optional_number?: pulumi.Input<number | undefined>;
+    optional_string?: pulumi.Input<string | undefined>;
     plain_optional_bool?: boolean;
     plain_optional_const?: "val";
     plain_optional_number?: number;
diff --git a/pkg/codegen/internal/test/testdata/plain-schema-gh6957/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/plain-schema-gh6957/nodejs/types/input.ts
index e1983a7e6..c89757f27 100644
--- a/pkg/codegen/internal/test/testdata/plain-schema-gh6957/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/plain-schema-gh6957/nodejs/types/input.ts
@@ -5,5 +5,5 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs } from "../types";
 
 export interface FooArgs {
-    a?: pulumi.Input<boolean>;
+    a?: pulumi.Input<boolean | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/provider-config-schema/nodejs/provider.ts b/pkg/codegen/internal/test/testdata/provider-config-schema/nodejs/provider.ts
index 129cc12b8..875fe49d8 100644
--- a/pkg/codegen/internal/test/testdata/provider-config-schema/nodejs/provider.ts
+++ b/pkg/codegen/internal/test/testdata/provider-config-schema/nodejs/provider.ts
@@ -48,5 +48,5 @@ export interface ProviderArgs {
     /**
      * this is a relaxed string enum which can also be set via env var
      */
-    favoriteColor?: pulumi.Input<string | enums.Color>;
+    favoriteColor?: pulumi.Input<string | enums.Color | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/person.ts b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/person.ts
index ae4dc79cb..43b1a673b 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/person.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/person.ts
@@ -63,6 +63,6 @@ export class Person extends pulumi.CustomResource {
  * The set of arguments for constructing a Person resource.
  */
 export interface PersonArgs {
-    name?: pulumi.Input<string>;
-    pets?: pulumi.Input<pulumi.Input<inputs.PetArgs>[]>;
+    name?: pulumi.Input<string | undefined>;
+    pets?: pulumi.Input<pulumi.Input<inputs.PetArgs>[] | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/pet.ts b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/pet.ts
index 1dd08f636..1aeaa16c8 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/pet.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/pet.ts
@@ -59,5 +59,5 @@ export class Pet extends pulumi.CustomResource {
  * The set of arguments for constructing a Pet resource.
  */
 export interface PetArgs {
-    name?: pulumi.Input<string>;
+    name?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/types/input.ts
index 5c75a701d..b58739524 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python-case-insensitive/nodejs/types/input.ts
@@ -5,5 +5,5 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs } from "../types";
 
 export interface PetArgs {
-    name?: pulumi.Input<string>;
+    name?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/person.ts b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/person.ts
index ae4dc79cb..43b1a673b 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/person.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/person.ts
@@ -63,6 +63,6 @@ export class Person extends pulumi.CustomResource {
  * The set of arguments for constructing a Person resource.
  */
 export interface PersonArgs {
-    name?: pulumi.Input<string>;
-    pets?: pulumi.Input<pulumi.Input<inputs.PetArgs>[]>;
+    name?: pulumi.Input<string | undefined>;
+    pets?: pulumi.Input<pulumi.Input<inputs.PetArgs>[] | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/pet.ts b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/pet.ts
index 1dd08f636..1aeaa16c8 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/pet.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/pet.ts
@@ -59,5 +59,5 @@ export class Pet extends pulumi.CustomResource {
  * The set of arguments for constructing a Pet resource.
  */
 export interface PetArgs {
-    name?: pulumi.Input<string>;
+    name?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/types/input.ts
index 5c75a701d..b58739524 100644
--- a/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/resource-args-python/nodejs/types/input.ts
@@ -5,5 +5,5 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs } from "../types";
 
 export interface PetArgs {
-    name?: pulumi.Input<string>;
+    name?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/nursery.ts b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/nursery.ts
index d9d03bb54..0298f0aef 100644
--- a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/nursery.ts
+++ b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/nursery.ts
@@ -65,7 +65,7 @@ export interface NurseryArgs {
     /**
      * The sizes of trees available
      */
-    sizes?: pulumi.Input<{[key: string]: pulumi.Input<enums.tree.v1.TreeSize>}>;
+    sizes?: pulumi.Input<{[key: string]: pulumi.Input<enums.tree.v1.TreeSize>} | undefined>;
     /**
      * The varieties available
      */
diff --git a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/rubberTree.ts b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/rubberTree.ts
index bb0613bcd..5a10c99fb 100644
--- a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/rubberTree.ts
+++ b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/tree/v1/rubberTree.ts
@@ -75,16 +75,16 @@ export class RubberTree extends pulumi.CustomResource {
 }
 
 export interface RubberTreeState {
-    farm?: pulumi.Input<enums.tree.v1.Farm | string>;
+    farm?: pulumi.Input<enums.tree.v1.Farm | string | undefined>;
 }
 
 /**
  * The set of arguments for constructing a RubberTree resource.
  */
 export interface RubberTreeArgs {
-    container?: pulumi.Input<inputs.ContainerArgs>;
+    container?: pulumi.Input<inputs.ContainerArgs | undefined>;
     diameter: pulumi.Input<enums.tree.v1.Diameter>;
-    farm?: pulumi.Input<enums.tree.v1.Farm | string>;
-    size?: pulumi.Input<enums.tree.v1.TreeSize>;
+    farm?: pulumi.Input<enums.tree.v1.Farm | string | undefined>;
+    size?: pulumi.Input<enums.tree.v1.TreeSize | undefined>;
     type: pulumi.Input<enums.tree.v1.RubberTreeVariety>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/types/input.ts
index 52f85fdca..7def568b8 100644
--- a/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/simple-enum-schema/nodejs/types/input.ts
@@ -5,8 +5,8 @@ import * as pulumi from "@pulumi/pulumi";
 import { input as inputs, output as outputs, enums } from "../types";
 
 export interface ContainerArgs {
-    brightness?: pulumi.Input<enums.ContainerBrightness>;
-    color?: pulumi.Input<enums.ContainerColor | string>;
-    material?: pulumi.Input<string>;
+    brightness?: pulumi.Input<enums.ContainerBrightness | undefined>;
+    color?: pulumi.Input<enums.ContainerColor | string | undefined>;
+    material?: pulumi.Input<string | undefined>;
     size: pulumi.Input<enums.ContainerSize>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-methods-schema-single-value-returns/nodejs/foo.ts b/pkg/codegen/internal/test/testdata/simple-methods-schema-single-value-returns/nodejs/foo.ts
index 02a470974..d4b3fdab0 100644
--- a/pkg/codegen/internal/test/testdata/simple-methods-schema-single-value-returns/nodejs/foo.ts
+++ b/pkg/codegen/internal/test/testdata/simple-methods-schema-single-value-returns/nodejs/foo.ts
@@ -61,8 +61,8 @@ export namespace Foo {
      * The set of arguments for the Foo.getKubeconfig method.
      */
     export interface GetKubeconfigArgs {
-        profileName?: pulumi.Input<string>;
-        roleArn?: pulumi.Input<string>;
+        profileName?: pulumi.Input<string | undefined>;
+        roleArn?: pulumi.Input<string | undefined>;
     }
 
     /**
diff --git a/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/foo.ts b/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/foo.ts
index 9176155c2..481905f43 100644
--- a/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/foo.ts
+++ b/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/foo.ts
@@ -91,16 +91,16 @@ export namespace Foo {
      * The set of arguments for the Foo.bar method.
      */
     export interface BarArgs {
-        baz?: pulumi.Input<inputs.nested.BazArgs>;
+        baz?: pulumi.Input<inputs.nested.BazArgs | undefined>;
         bazPlain?: inputs.nested.BazArgs;
         bazRequired: pulumi.Input<inputs.nested.BazArgs>;
-        boolValue?: pulumi.Input<boolean>;
+        boolValue?: pulumi.Input<boolean | undefined>;
         boolValuePlain?: boolean;
         boolValueRequired: pulumi.Input<boolean>;
-        name?: pulumi.Input<pulumiRandom.RandomPet>;
+        name?: pulumi.Input<pulumiRandom.RandomPet | undefined>;
         namePlain?: pulumiRandom.RandomPet;
         nameRequired: pulumi.Input<pulumiRandom.RandomPet>;
-        stringValue?: pulumi.Input<string>;
+        stringValue?: pulumi.Input<string | undefined>;
         stringValuePlain?: string;
         stringValueRequired: pulumi.Input<string>;
     }
diff --git a/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/types/input.ts
index e144ff619..69ef1e106 100644
--- a/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/simple-methods-schema/nodejs/types/input.ts
@@ -11,7 +11,7 @@ export namespace nested {
     }
 
     export interface BazArgs {
-        hello?: pulumi.Input<string>;
-        world?: pulumi.Input<string>;
+        hello?: pulumi.Input<string | undefined>;
+        world?: pulumi.Input<string | undefined>;
     }
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-plain-schema-with-root-package/nodejs/component.ts b/pkg/codegen/internal/test/testdata/simple-plain-schema-with-root-package/nodejs/component.ts
index 727d54c2d..73ee16aec 100644
--- a/pkg/codegen/internal/test/testdata/simple-plain-schema-with-root-package/nodejs/component.ts
+++ b/pkg/codegen/internal/test/testdata/simple-plain-schema-with-root-package/nodejs/component.ts
@@ -89,5 +89,5 @@ export interface ComponentArgs {
     d?: number;
     e: string;
     f?: string;
-    foo?: pulumi.Input<inputs.FooArgs>;
+    foo?: pulumi.Input<inputs.FooArgs | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-plain-schema/nodejs/component.ts b/pkg/codegen/internal/test/testdata/simple-plain-schema/nodejs/component.ts
index 21e5e7957..c639a9215 100644
--- a/pkg/codegen/internal/test/testdata/simple-plain-schema/nodejs/component.ts
+++ b/pkg/codegen/internal/test/testdata/simple-plain-schema/nodejs/component.ts
@@ -91,5 +91,5 @@ export interface ComponentArgs {
     d?: number;
     e: string;
     f?: string;
-    foo?: pulumi.Input<inputs.FooArgs>;
+    foo?: pulumi.Input<inputs.FooArgs | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/argFunction.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/argFunction.ts
index fee6970d5..0b8997578 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/argFunction.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/argFunction.ts
@@ -33,5 +33,5 @@ export function argFunctionOutput(args?: ArgFunctionOutputArgs, opts?: pulumi.In
 }
 
 export interface ArgFunctionOutputArgs {
-    arg1?: pulumi.Input<Resource>;
+    arg1?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/otherResource.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/otherResource.ts
index ad157d4a9..a84662da4 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/otherResource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/otherResource.ts
@@ -49,5 +49,5 @@ export class OtherResource extends pulumi.ComponentResource {
  * The set of arguments for constructing a OtherResource resource.
  */
 export interface OtherResourceArgs {
-    foo?: pulumi.Input<Resource>;
+    foo?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/resource.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/resource.ts
index e94097d4d..7052b1d7d 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/resource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema-custom-pypackage-name/nodejs/resource.ts
@@ -59,5 +59,5 @@ export class Resource extends pulumi.CustomResource {
  * The set of arguments for constructing a Resource resource.
  */
 export interface ResourceArgs {
-    bar?: pulumi.Input<string>;
+    bar?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/argFunction.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/argFunction.ts
index fee6970d5..0b8997578 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/argFunction.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/argFunction.ts
@@ -33,5 +33,5 @@ export function argFunctionOutput(args?: ArgFunctionOutputArgs, opts?: pulumi.In
 }
 
 export interface ArgFunctionOutputArgs {
-    arg1?: pulumi.Input<Resource>;
+    arg1?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/otherResource.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/otherResource.ts
index ad157d4a9..a84662da4 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/otherResource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/otherResource.ts
@@ -49,5 +49,5 @@ export class OtherResource extends pulumi.ComponentResource {
  * The set of arguments for constructing a OtherResource resource.
  */
 export interface OtherResourceArgs {
-    foo?: pulumi.Input<Resource>;
+    foo?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/resource.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/resource.ts
index 8acb090c1..ffcd5d993 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/resource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/resource.ts
@@ -61,5 +61,5 @@ export class Resource extends pulumi.CustomResource {
  * The set of arguments for constructing a Resource resource.
  */
 export interface ResourceArgs {
-    bar?: pulumi.Input<string>;
+    bar?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/typeUses.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/typeUses.ts
index 9f76fd868..c9b4de490 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/typeUses.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/typeUses.ts
@@ -68,7 +68,7 @@ export class TypeUses extends pulumi.CustomResource {
  * The set of arguments for constructing a TypeUses resource.
  */
 export interface TypeUsesArgs {
-    bar?: pulumi.Input<inputs.SomeOtherObjectArgs>;
-    baz?: pulumi.Input<inputs.ObjectWithNodeOptionalInputsArgs>;
-    foo?: pulumi.Input<inputs.ObjectArgs>;
+    bar?: pulumi.Input<inputs.SomeOtherObjectArgs | undefined>;
+    baz?: pulumi.Input<inputs.ObjectWithNodeOptionalInputsArgs | undefined>;
+    foo?: pulumi.Input<inputs.ObjectArgs | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/types/input.ts
index ce174713d..8a3605fad 100644
--- a/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/simple-resource-schema/nodejs/types/input.ts
@@ -7,28 +7,28 @@ import { input as inputs, output as outputs } from "../types";
 import {Resource} from "..";
 
 export interface ConfigMapArgs {
-    config?: pulumi.Input<string>;
+    config?: pulumi.Input<string | undefined>;
 }
 
 export interface ObjectArgs {
-    bar?: pulumi.Input<string>;
-    configs?: pulumi.Input<pulumi.Input<inputs.ConfigMapArgs>[]>;
-    foo?: pulumi.Input<Resource>;
+    bar?: pulumi.Input<string | undefined>;
+    configs?: pulumi.Input<pulumi.Input<inputs.ConfigMapArgs>[] | undefined>;
+    foo?: pulumi.Input<Resource | undefined>;
     /**
      * List of lists of other objects
      */
-    others?: pulumi.Input<pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>[]>;
+    others?: pulumi.Input<pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>[] | undefined>;
     /**
      * Mapping from string to list of some other object
      */
-    stillOthers?: pulumi.Input<{[key: string]: pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>}>;
+    stillOthers?: pulumi.Input<{[key: string]: pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>} | undefined>;
 }
 
 export interface ObjectWithNodeOptionalInputsArgs {
-    bar?: pulumi.Input<number>;
-    foo?: pulumi.Input<string>;
+    bar?: pulumi.Input<number | undefined>;
+    foo?: pulumi.Input<string | undefined>;
 }
 
 export interface SomeOtherObjectArgs {
-    baz?: pulumi.Input<string>;
+    baz?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/argFunction.ts b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/argFunction.ts
index fee6970d5..0b8997578 100644
--- a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/argFunction.ts
+++ b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/argFunction.ts
@@ -33,5 +33,5 @@ export function argFunctionOutput(args?: ArgFunctionOutputArgs, opts?: pulumi.In
 }
 
 export interface ArgFunctionOutputArgs {
-    arg1?: pulumi.Input<Resource>;
+    arg1?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/otherResource.ts b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/otherResource.ts
index 58de90c93..fab1e6679 100644
--- a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/otherResource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/otherResource.ts
@@ -51,5 +51,5 @@ export class OtherResource extends pulumi.ComponentResource {
  */
 export interface OtherResourceArgs {
     bar?: pulumi.Input<string>[];
-    foo?: pulumi.Input<Resource>;
+    foo?: pulumi.Input<Resource | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/resource.ts b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/resource.ts
index 8acb090c1..ffcd5d993 100644
--- a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/resource.ts
+++ b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/resource.ts
@@ -61,5 +61,5 @@ export class Resource extends pulumi.CustomResource {
  * The set of arguments for constructing a Resource resource.
  */
 export interface ResourceArgs {
-    bar?: pulumi.Input<string>;
+    bar?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/typeUses.ts b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/typeUses.ts
index fea9057d7..dbfbcfc14 100644
--- a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/typeUses.ts
+++ b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/typeUses.ts
@@ -71,8 +71,8 @@ export class TypeUses extends pulumi.CustomResource {
  * The set of arguments for constructing a TypeUses resource.
  */
 export interface TypeUsesArgs {
-    bar?: pulumi.Input<inputs.SomeOtherObjectArgs>;
-    baz?: pulumi.Input<inputs.ObjectWithNodeOptionalInputsArgs>;
-    foo?: pulumi.Input<inputs.ObjectArgs>;
-    qux?: pulumi.Input<enums.RubberTreeVariety>;
+    bar?: pulumi.Input<inputs.SomeOtherObjectArgs | undefined>;
+    baz?: pulumi.Input<inputs.ObjectWithNodeOptionalInputsArgs | undefined>;
+    foo?: pulumi.Input<inputs.ObjectArgs | undefined>;
+    qux?: pulumi.Input<enums.RubberTreeVariety | undefined>;
 }
diff --git a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/types/input.ts b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/types/input.ts
index 0ca71d478..95e034370 100644
--- a/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/types/input.ts
+++ b/pkg/codegen/internal/test/testdata/simple-yaml-schema/nodejs/types/input.ts
@@ -7,28 +7,28 @@ import { input as inputs, output as outputs, enums } from "../types";
 import {Resource} from "..";
 
 export interface ConfigMapArgs {
-    config?: pulumi.Input<string>;
+    config?: pulumi.Input<string | undefined>;
 }
 
 export interface ObjectArgs {
-    bar?: pulumi.Input<string>;
-    configs?: pulumi.Input<pulumi.Input<inputs.ConfigMapArgs>[]>;
-    foo?: pulumi.Input<Resource>;
+    bar?: pulumi.Input<string | undefined>;
+    configs?: pulumi.Input<pulumi.Input<inputs.ConfigMapArgs>[] | undefined>;
+    foo?: pulumi.Input<Resource | undefined>;
     /**
      * List of lists of other objects
      */
-    others?: pulumi.Input<pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>[]>;
+    others?: pulumi.Input<pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>[] | undefined>;
     /**
      * Mapping from string to list of some other object
      */
-    stillOthers?: pulumi.Input<{[key: string]: pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>}>;
+    stillOthers?: pulumi.Input<{[key: string]: pulumi.Input<pulumi.Input<inputs.SomeOtherObjectArgs>[]>} | undefined>;
 }
 
 export interface ObjectWithNodeOptionalInputsArgs {
-    bar?: pulumi.Input<number>;
-    foo?: pulumi.Input<string>;
+    bar?: pulumi.Input<number | undefined>;
+    foo?: pulumi.Input<string | undefined>;
 }
 
 export interface SomeOtherObjectArgs {
-    baz?: pulumi.Input<string>;
+    baz?: pulumi.Input<string | undefined>;
 }
diff --git a/pkg/codegen/internal/tstypes/tstypes.go b/pkg/codegen/internal/tstypes/tstypes.go
index d0ca9a5f9..49e9e29c6 100644
--- a/pkg/codegen/internal/tstypes/tstypes.go
+++ b/pkg/codegen/internal/tstypes/tstypes.go
@@ -68,6 +68,14 @@ func Union(t ...TypeAst) TypeAst {
 	return &unionType{t[0], t[1], t[2:]}
 }
 
+// IsUnion returns true if the AST node is a union.
+func IsUnion(t TypeAst) ([]TypeAst, bool) {
+	if union, ok := t.(*unionType); ok {
+		return union.all(), true
+	}
+	return nil, false
+}
+
 // Normalizes by unnesting unions `A | (B | C) => A | B | C`.
 func Normalize(ast TypeAst) TypeAst {
 	return transform(ast, func(t TypeAst) TypeAst {
diff --git a/pkg/codegen/nodejs/gen.go b/pkg/codegen/nodejs/gen.go
index 0bfcb4a2a..e516da3c0 100644
--- a/pkg/codegen/nodejs/gen.go
+++ b/pkg/codegen/nodejs/gen.go
@@ -432,13 +432,15 @@ func (mod *modContext) genPlainType(w io.Writer, name, comment string, propertie
 			prefix = "readonly "
 		}
 
-		sigil, propertyType := "", p.Type
-		if !p.IsRequired() {
-			sigil, propertyType = "?", codegen.RequiredType(p)
+		sigil, typ := "", mod.typeAst(p.Type, input, p.ConstValue)
+		if types, ok := tstypes.IsUnion(typ); ok {
+			if id, ok := tstypes.IsIdentifier(types[len(types)-1]); ok && id == "undefined" {
+				sigil, typ = "?", tstypes.Union(types[:len(types)-1]...)
+			}
 		}
 
-		typ := mod.typeString(propertyType, input, p.ConstValue)
-		fmt.Fprintf(w, "%s    %s%s%s: %s;\n", indent, prefix, p.Name, sigil, typ)
+		typLit := tstypes.TypeLiteral(tstypes.Normalize(typ))
+		fmt.Fprintf(w, "%s    %s%s%s: %s;\n", indent, prefix, p.Name, sigil, typLit)
 	}
 	fmt.Fprintf(w, "%s}\n", indent)
 }