diff --git a/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache b/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
index 0e66e19302c..e5b54a1d852 100644
--- a/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
@@ -87,37 +87,37 @@ export function {{classname}}FromJSONTyped(json: any, ignoreDiscriminator: boole
         if (json.every(item => typeof item === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}})) {
             return json;
         }
-     }
+    }
     {{/isNumeric}}
     {{#isString}}
     if (Array.isArray(json)) {
         if (json.every(item => typeof item === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}})) {
             return json;
         }
-     }
+    }
     {{/isString}}
     {{/items}}
     {{/isArray}}
     {{^isArray}}
     {{#isDateType}}
-    if(!(isNaN(new Date(json).getTime()))) {
+    if (!(isNaN(new Date(json).getTime()))) {
         return {{^required}}json == null ? undefined : {{/required}}({{#required}}{{#isNullable}}json == null ? null : {{/isNullable}}{{/required}}new Date(json));
     }
     {{/isDateType}}
     {{^isDateType}}
     {{#isDateTimeType}}
-    if(!(isNaN(new Date(json).getTime()))) {
+    if (!(isNaN(new Date(json).getTime()))) {
         return {{^required}}json == null ? undefined : {{/required}}({{#required}}{{#isNullable}}json == null ? null : {{/isNullable}}{{/required}}new Date(json));
     }
     {{/isDateTimeType}}
     {{/isDateType}}
     {{#isNumeric}}
-    if(typeof json === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}json === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+    if (typeof json === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}json === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
         return json;
     }
     {{/isNumeric}}
     {{#isString}}
-    if(typeof json === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}json === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+    if (typeof json === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}json === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
         return json;
     }
     {{/isString}}
@@ -189,14 +189,14 @@ export function {{classname}}ToJSONTyped(value?: {{classname}} | null, ignoreDis
     {{/isDateTimeType}}
     {{#isNumeric}}
     if (Array.isArray(value)) {
-        if (value.every(item => typeof item === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+        if (value.every(item => typeof item === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}})) {
             return value;
         }
     }
     {{/isNumeric}}
     {{#isString}}
     if (Array.isArray(value)) {
-        if (value.every(item => typeof item === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+        if (value.every(item => typeof item === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}item === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}})) {
             return value;
         }
     }
@@ -205,22 +205,22 @@ export function {{classname}}ToJSONTyped(value?: {{classname}} | null, ignoreDis
     {{/isArray}}
     {{^isArray}}
     {{#isDateType}}
-    if(value instanceof Date) {
+    if (value instanceof Date) {
         return ((value{{#isNullable}} as any{{/isNullable}}){{^required}}{{#isNullable}}?{{/isNullable}}{{/required}}.toISOString().substring(0,10));
-     }
+    }
     {{/isDateType}}
     {{#isDateTimeType}}
-    if(value instanceof Date) {
+    if (value instanceof Date) {
         return {{^required}}{{#isNullable}}value === null ? null : {{/isNullable}}{{^isNullable}}value == null ? undefined : {{/isNullable}}{{/required}}((value{{#isNullable}} as any{{/isNullable}}){{^required}}{{#isNullable}}?{{/isNullable}}{{/required}}.toISOString());
     }
     {{/isDateTimeType}}
     {{#isNumeric}}
-    if(typeof value === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}value === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+    if (typeof value === 'number'{{#isEnum}} && ({{#allowableValues}}{{#values}}value === {{.}}{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
         return value;
     }
     {{/isNumeric}}
     {{#isString}}
-    if(typeof value === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}value === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
+    if (typeof value === 'string'{{#isEnum}} && ({{#allowableValues}}{{#values}}value === '{{.}}'{{^-last}} || {{/-last}}{{/values}}{{/allowableValues}}){{/isEnum}}) {
         return value;
     }
     {{/isString}}
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
index e8a93a8f947..fb592791521 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
@@ -356,19 +356,21 @@ public class TypeScriptFetchClientCodegenTest {
 
         Path exampleModelPath = Paths.get(outputPath + "/models/MyCustomSpeed.ts");
         //FromJSON
-        TestUtils.assertFileContains(exampleModelPath, "typeof json === 'number'");
-        TestUtils.assertFileContains(exampleModelPath, "typeof json === 'string'");
-        TestUtils.assertFileContains(exampleModelPath, "json === 'fixed-value-a' || json === 'fixed-value-b' || json === 'fixed-value-c'");
-        TestUtils.assertFileContains(exampleModelPath, "isNaN(new Date(json).getTime())");
-        TestUtils.assertFileContains(exampleModelPath, "json.every(item => typeof item === 'number'");
-        TestUtils.assertFileContains(exampleModelPath, "json.every(item => typeof item === 'string' && (item === 'oneof-array-enum-a' || item === 'oneof-array-enum-b' || item === 'oneof-array-enum-c')");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof json !== 'object')");
+        TestUtils.assertFileContains(exampleModelPath, "(instanceOfMyNumericValue(json))");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof json === 'number' && (json === 10 || json === 20 || json === 30))");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof json === 'string' && (json === 'fixed-value-a' || json === 'fixed-value-b' || json === 'fixed-value-c'))");
+        TestUtils.assertFileContains(exampleModelPath, "(isNaN(new Date(json).getTime())");
+        TestUtils.assertFileContains(exampleModelPath, "(json.every(item => typeof item === 'number'))");
+        TestUtils.assertFileContains(exampleModelPath, "(json.every(item => typeof item === 'string' && (item === 'oneof-array-enum-a' || item === 'oneof-array-enum-b' || item === 'oneof-array-enum-c')))");
         //ToJSON
-        TestUtils.assertFileContains(exampleModelPath, "typeof value === 'number'");
-        TestUtils.assertFileContains(exampleModelPath, "typeof value === 'string'");
-        TestUtils.assertFileContains(exampleModelPath, "value === 'fixed-value-a' || value === 'fixed-value-b' || value === 'fixed-value-c'");
-        TestUtils.assertFileContains(exampleModelPath, "value instanceof Date");
-        TestUtils.assertFileContains(exampleModelPath, "value.every(item => typeof item === 'number'");
-        TestUtils.assertFileContains(exampleModelPath, "value.every(item => typeof item === 'string' && (item === 'oneof-array-enum-a' || item === 'oneof-array-enum-b' || item === 'oneof-array-enum-c')");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof value !== 'object')");
+        TestUtils.assertFileContains(exampleModelPath, "(instanceOfMyNumericValue(value))");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof value === 'number' && (value === 10 || value === 20 || value === 30))");
+        TestUtils.assertFileContains(exampleModelPath, "(typeof value === 'string' && (value === 'fixed-value-a' || value === 'fixed-value-b' || value === 'fixed-value-c'))");
+        TestUtils.assertFileContains(exampleModelPath, "(value instanceof Date)");
+        TestUtils.assertFileContains(exampleModelPath, "(value.every(item => typeof item === 'number'))");
+        TestUtils.assertFileContains(exampleModelPath, "(value.every(item => typeof item === 'string' && (item === 'oneof-array-enum-a' || item === 'oneof-array-enum-b' || item === 'oneof-array-enum-c')))");
     }
 
     /**
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
index a7a3e644f0b..1795a90ef93 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
@@ -47,7 +47,7 @@ import static io.swagger.codegen.utils.ModelUtils.updateCodegenPropertyEnum;
 @SuppressWarnings("static-method")
 public class TypeScriptFetchModelTest {
 
-    @Test(description = "convert a simple TypeScript Angular model")
+    @Test(description = "convert a simple TypeScript Fetch model")
     public void simpleModelTest() {
         final Schema model = new Schema()
                 .description("a sample model")
diff --git a/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestArrayResponse.ts b/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestArrayResponse.ts
index ed4b8124582..29e0eb1017e 100644
--- a/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestArrayResponse.ts
+++ b/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestArrayResponse.ts
@@ -57,7 +57,7 @@ export function TestArrayResponseFromJSONTyped(json: any, ignoreDiscriminator: b
         if (json.every(item => typeof item === 'string')) {
             return json;
         }
-     }
+    }
     return {} as any;
 }
 
@@ -81,7 +81,7 @@ export function TestArrayResponseToJSONTyped(value?: TestArrayResponse | null, i
         return value;
     }
     if (Array.isArray(value)) {
-        if (value.every(item => typeof item === 'string') {
+        if (value.every(item => typeof item === 'string')) {
             return value;
         }
     }
diff --git a/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestResponse.ts b/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestResponse.ts
index 466c781097c..031d545e20b 100644
--- a/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestResponse.ts
+++ b/samples/client/petstore/typescript-fetch/builds/oneOf/models/TestResponse.ts
@@ -51,7 +51,7 @@ export function TestResponseFromJSONTyped(json: any, ignoreDiscriminator: boolea
     if (instanceOfTestB(json)) {
         return TestBFromJSONTyped(json, true);
     }
-    if(typeof json === 'string') {
+    if (typeof json === 'string') {
         return json;
     }
     return {} as any;
@@ -74,7 +74,7 @@ export function TestResponseToJSONTyped(value?: TestResponse | null, ignoreDiscr
     if (instanceOfTestB(value)) {
         return TestBToJSON(value as TestB);
     }
-    if(typeof value === 'string') {
+    if (typeof value === 'string') {
         return value;
     }
     return {};