diff --git a/src/generate.ts b/src/generate.ts
index c4e6464e..afd25343 100644
--- a/src/generate.ts
+++ b/src/generate.ts
@@ -126,7 +126,7 @@ const getRouteDeclaration = (
     pathTemplate,
     {
       [method]: {
-        parameters: parameters.length > 0 ? parameters : undefined,
+        ...(parameters.length > 0 ? { parameters } : undefined),
         ...operationRequestBody(requestBody),
         responses,
       },
@@ -395,7 +395,7 @@ const typeToSchema = (
   type: ts.Type,
   optional = false
 ): OpenAPIV3.SchemaObject | undefined => {
-  let nullable: { nullable?: true } = {}
+  let nullable: { nullable: true } | undefined
 
   if (type.isUnion()) {
     let elems = type.types
diff --git a/tests/__snapshots__/generate.spec.ts.snap b/tests/__snapshots__/generate.spec.ts.snap
index 4b0e5ce3..3c5d1e7a 100644
--- a/tests/__snapshots__/generate.spec.ts.snap
+++ b/tests/__snapshots__/generate.spec.ts.snap
@@ -7,7 +7,6 @@ Array [
     "paths": Object {
       "/branded-request-body": Object {
         "post": Object {
-          "parameters": undefined,
           "requestBody": Object {
             "content": Object {
               "application/json": Object {
@@ -51,7 +50,6 @@ Array [
       },
       "/constant": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {
@@ -68,7 +66,6 @@ Array [
       },
       "/direct-route-call": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {
@@ -85,7 +82,6 @@ Array [
       },
       "/interface-response": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {
@@ -115,7 +111,6 @@ Array [
       },
       "/no-explicit-route-type": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {
@@ -170,7 +165,6 @@ Array [
       },
       "/request-body": Object {
         "post": Object {
-          "parameters": undefined,
           "requestBody": Object {
             "content": Object {
               "application/json": Object {
@@ -272,7 +266,6 @@ Array [
       },
       "/response-headers": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {
@@ -297,7 +290,6 @@ Array [
       },
       "/unused-request": Object {
         "get": Object {
-          "parameters": undefined,
           "responses": Object {
             "200": Object {
               "content": Object {