diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
index bc7473f9f861..80c2da63d39b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
@@ -103,6 +103,9 @@ public class TypeScriptFetchClientCodegen extends AbstractTypeScriptClientCodege
     private static final String X_KEEP_AS_JS_OBJECT = "x-keepAsJSObject";
     private static final String X_TYPESCRIPT_FETCH_API_EXAMPLE = "x-typescriptFetchApiExample";
     private static final String BLOB_API_EXAMPLE = "new Blob(['example file content'], { type: 'application/octet-stream' })";
+    private static final String DATE_TYPE = "date";
+    private static final String DATE_TIME_TYPE = "DateTime";
+    private static final String TS_DATE_TYPE = "Date";
 
     protected boolean sagasAndRecords = false;
     @Getter @Setter
@@ -317,8 +320,8 @@ public void processOpts() {
 
         if (!withoutRuntimeChecks) {
             this.modelTemplateFiles.put("models.mustache", ".ts");
-            typeMapping.put("date", "Date");
-            typeMapping.put("DateTime", "Date");
+            typeMapping.put(DATE_TYPE, TS_DATE_TYPE);
+            typeMapping.put(DATE_TIME_TYPE, TS_DATE_TYPE);
         }
 
         if (additionalProperties.containsKey(SAGAS_AND_RECORDS)) {
@@ -1484,11 +1487,11 @@ public String getItemsDataType() {
         }
 
         public boolean isDateType() {
-            return isDate && "Date".equals(dataType);
+            return isDate && TypeScriptFetchClientCodegen.isDateType(dataType);
         }
 
         public boolean isDateTimeType() {
-            return isDateTime && "Date".equals(dataType);
+            return isDateTime && TypeScriptFetchClientCodegen.isDateTimeType(dataType);
         }
 
         public ExtendedCodegenParameter(CodegenParameter cp) {
@@ -1635,11 +1638,11 @@ public String getItemsDataType() {
         }
 
         public boolean isDateType() {
-            return isDate && "Date".equals(dataType);
+            return isDate && TypeScriptFetchClientCodegen.isDateType(dataType);
         }
 
         public boolean isDateTimeType() {
-            return isDateTime && "Date".equals(dataType);
+            return isDateTime && TypeScriptFetchClientCodegen.isDateTimeType(dataType);
         }
 
         public ExtendedCodegenProperty(CodegenProperty cp) {
@@ -1923,12 +1926,13 @@ public class ExtendedCodegenModel extends CodegenModel {
         public boolean hasSelfReferencingDiscriminatorMapping(){
             return selfReferencingDiscriminatorMapping != null;
         }
+
         public boolean isDateType() {
-            return isDate && "Date".equals(dataType);
+            return isDate && TypeScriptFetchClientCodegen.isDateType(dataType);
         }
 
         public boolean isDateTimeType() {
-            return isDateTime && "Date".equals(dataType);
+            return isDateTime && TypeScriptFetchClientCodegen.isDateTimeType(dataType);
         }
 
         public ExtendedCodegenModel(CodegenModel cm) {
@@ -2069,4 +2073,12 @@ public String toString() {
     protected String getLicenseNameDefaultValue() {
         return null;
     }
+
+    private static boolean isDateType(String dataType) {
+        return TS_DATE_TYPE.equals(dataType);
+    }
+
+    private static boolean isDateTimeType(String dataType) {
+        return TS_DATE_TYPE.equals(dataType);
+    }
 }