[typescript-fetch] Make instanceOf infer type and check for undefineds (OpenAPITools#18694)

Author: rickyrombo

modules/openapi-generator/src/main/resources/typescript-fetch/modelGeneric.mustache

@@ -20,10 +20,10 @@ import { {{modelName}}FromJSONTyped } from './{{modelName}}{{importFileExtension
 /**
  * Check if a given object implements the {{classname}} interface.
  */
-export function instanceOf{{classname}}(value: object): boolean {
+export function instanceOf{{classname}}(value: object): value is {{classname}} {
     {{#vars}}
     {{#required}}
-    if (!('{{name}}' in value)) return false;
+    if (!('{{name}}' in value) || value['{{name}}'] === undefined) return false;
     {{/required}}
     {{/vars}}
     return true;

samples/client/petstore/typescript-fetch/builds/allOf-nullable/models/Club.ts

@@ -37,7 +37,7 @@ export interface Club {
 /**
  * Check if a given object implements the Club interface.
  */
-export function instanceOfClub(value: object): boolean {
+export function instanceOfClub(value: object): value is Club {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/allOf-nullable/models/Owner.ts

@@ -30,7 +30,7 @@ export interface Owner {
 /**
  * Check if a given object implements the Owner interface.
  */
-export function instanceOfOwner(value: object): boolean {
+export function instanceOfOwner(value: object): value is Owner {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/allOf-readonly/models/Club.ts

@@ -37,7 +37,7 @@ export interface Club {
 /**
  * Check if a given object implements the Club interface.
  */
-export function instanceOfClub(value: object): boolean {
+export function instanceOfClub(value: object): value is Club {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/allOf-readonly/models/Owner.ts

@@ -30,7 +30,7 @@ export interface Owner {
 /**
  * Check if a given object implements the Owner interface.
  */
-export function instanceOfOwner(value: object): boolean {
+export function instanceOfOwner(value: object): value is Owner {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/default-v3.0/models/AdditionalPropertiesClass.ts

@@ -36,7 +36,7 @@ export interface AdditionalPropertiesClass {
 /**
  * Check if a given object implements the AdditionalPropertiesClass interface.
  */
-export function instanceOfAdditionalPropertiesClass(value: object): boolean {
+export function instanceOfAdditionalPropertiesClass(value: object): value is AdditionalPropertiesClass {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/default-v3.0/models/AllOfWithSingleRef.ts

@@ -43,7 +43,7 @@ export interface AllOfWithSingleRef {
 /**
  * Check if a given object implements the AllOfWithSingleRef interface.
  */
-export function instanceOfAllOfWithSingleRef(value: object): boolean {
+export function instanceOfAllOfWithSingleRef(value: object): value is AllOfWithSingleRef {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/default-v3.0/models/Animal.ts

@@ -38,8 +38,8 @@ export interface Animal {
 /**
  * Check if a given object implements the Animal interface.
  */
-export function instanceOfAnimal(value: object): boolean {
-    if (!('className' in value)) return false;
+export function instanceOfAnimal(value: object): value is Animal {
+    if (!('className' in value) || value['className'] === undefined) return false;
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/default-v3.0/models/ArrayOfArrayOfNumberOnly.ts

@@ -30,7 +30,7 @@ export interface ArrayOfArrayOfNumberOnly {
 /**
  * Check if a given object implements the ArrayOfArrayOfNumberOnly interface.
  */
-export function instanceOfArrayOfArrayOfNumberOnly(value: object): boolean {
+export function instanceOfArrayOfArrayOfNumberOnly(value: object): value is ArrayOfArrayOfNumberOnly {
     return true;
 }
 

samples/client/petstore/typescript-fetch/builds/default-v3.0/models/ArrayOfNumberOnly.ts

@@ -30,7 +30,7 @@ export interface ArrayOfNumberOnly {
 /**
  * Check if a given object implements the ArrayOfNumberOnly interface.
  */
-export function instanceOfArrayOfNumberOnly(value: object): boolean {
+export function instanceOfArrayOfNumberOnly(value: object): value is ArrayOfNumberOnly {
     return true;
 }