diff --git a/src/etapi/notes.ts b/src/etapi/notes.ts
index fcb2d314f..620e9f3d8 100644
--- a/src/etapi/notes.ts
+++ b/src/etapi/notes.ts
@@ -239,6 +239,10 @@ function parseBoolean(obj: any, name: string) {
 }
 
 function parseOrderDirection(obj: any, name: string) {
+    if (!(name in obj)) {
+        return undefined;
+    }
+
     const integer = parseInt(obj[name]);
 
     if (!['asc', 'desc'].includes(obj[name])) {
diff --git a/src/etapi/spec.ts b/src/etapi/spec.ts
index ed8a555a5..530249d46 100644
--- a/src/etapi/spec.ts
+++ b/src/etapi/spec.ts
@@ -4,7 +4,7 @@ import fs = require('fs');
 import path = require('path');
 
 const specPath = path.join(__dirname, 'etapi.openapi.yaml');
-let spec: any = null;
+let spec: string | null = null;
 
 function register(router: Router) {
     router.get('/etapi/etapi.openapi.yaml', (req, res, next) => {
diff --git a/src/etapi/validators.ts b/src/etapi/validators.ts
index 485bd8d33..a8e98882e 100644
--- a/src/etapi/validators.ts
+++ b/src/etapi/validators.ts
@@ -24,7 +24,7 @@ function isString(obj: ValidatorArg) {
 }
 
 function isLocalDateTime(obj: ValidatorArg) {
-    if (obj === undefined || obj === null || typeof obj !== "string") {
+    if (typeof obj !== "string") {
         return;
     }
 
@@ -32,7 +32,7 @@ function isLocalDateTime(obj: ValidatorArg) {
 }
 
 function isUtcDateTime(obj: ValidatorArg) {
-    if (obj === undefined || obj === null || typeof obj !== "string") {
+    if (typeof obj !== "string") {
         return;
     }