fix(typescript): add trailing commas to as const enums (#23275)

Keep enum object diffs smaller across Angular, Fetch, and NestJS server generators.

Author: scarf005

modules/openapi-generator/src/main/resources/typescript-angular/modelEnum.mustache

@@ -22,7 +22,7 @@ export const {{classname}} = {
      * {{.}}
      */
 {{/enumDescription}}
-    {{name}}: {{{value}}}{{^-last}},{{/-last}}
+    {{name}}: {{{value}}},
 {{/enumVars}}
 {{/allowableValues}}
 } as const;

modules/openapi-generator/src/main/resources/typescript-angular/modelGenericEnums.mustache

@@ -18,7 +18,7 @@ export enum {{classname}}{{enumName}} {
     export const {{enumName}} = {
     {{#allowableValues}}
     {{#enumVars}}
-        {{name}}: {{{value}}}{{^-last}},{{/-last}}
+        {{name}}: {{{value}}},
     {{/enumVars}}
     {{/allowableValues}}
     } as const;
@@ -27,4 +27,4 @@ export enum {{classname}}{{enumName}} {
     {{/isEnum}}
 {{/vars}}
 {{^stringEnums}}}{{/stringEnums}}
-{{/hasEnums}}
+{{/hasEnums}}

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

@@ -496,7 +496,7 @@ export enum {{operationIdCamelCase}}{{enumName}} {
 export const {{operationIdCamelCase}}{{enumName}} = {
 {{#allowableValues}}
     {{#enumVars}}
-    {{{name}}}: {{{value}}}{{^-last}},{{/-last}}
+    {{{name}}}: {{{value}}},
     {{/enumVars}}
 {{/allowableValues}}
 } as const;

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

@@ -29,9 +29,9 @@ export const {{classname}} = {
     * {{enumDescription}}
     */
     {{/enumDescription}}
-    {{{name}}}: {{{value}}}{{^-last}},{{/-last}}
+    {{{name}}}: {{{value}}},
 {{/enumVars}}
 {{/allowableValues}}
 } as const;
 export type {{classname}} = typeof {{classname}}[keyof typeof {{classname}}];
-{{/stringEnums}}
+{{/stringEnums}}

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

@@ -41,10 +41,10 @@ export enum {{classname}}{{enumName}} {
 export const {{classname}}{{enumName}} = {
 {{#allowableValues}}
     {{#enumVars}}
-    {{{name}}}: {{{value}}}{{^-last}},{{/-last}}
+    {{{name}}}: {{{value}}},
     {{/enumVars}}
 {{/allowableValues}}
 } as const;
 export type {{classname}}{{enumName}} = typeof {{classname}}{{enumName}}[keyof typeof {{classname}}{{enumName}}];
 {{/stringEnums}}
-{{/isEnum}}{{/vars}}{{/hasEnums}}{{>validationAttributes}}
+{{/isEnum}}{{/vars}}{{/hasEnums}}{{>validationAttributes}}

modules/openapi-generator/src/main/resources/typescript-nestjs-server/modelEnum.mustache

@@ -22,7 +22,7 @@ export const {{classname}} = {
      * {{.}}
      */
 {{/enumDescription}}
-    {{name}}: {{{value}}}{{^-last}},{{/-last}}
+    {{name}}: {{{value}}},
 {{/enumVars}}
 {{/allowableValues}}
 } as const;

modules/openapi-generator/src/main/resources/typescript-nestjs-server/modelGenericEnums.mustache

@@ -18,7 +18,7 @@ export namespace {{classname}} {
   export const {{enumName}} = {
   {{#allowableValues}}
   {{#enumVars}}
-    {{name}}: {{{value}}}{{^-last}},{{/-last}}
+    {{name}}: {{{value}}},
   {{/enumVars}}
   {{/allowableValues}}
   } as const;
@@ -27,4 +27,4 @@ export namespace {{classname}} {
     {{/isEnum}}
 {{/vars}}
 {{^stringEnums}}}{{/stringEnums}}
-{{/hasEnums}}
+{{/hasEnums}}

modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/SharedTypeScriptTest.java

@@ -4,6 +4,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -274,6 +275,32 @@ public void givenMapWithArrayOfEnumsThenCorrectEnumNameIsUsed() throws Exception
         }
     }
 
+    @Test(description = "Issue #23275 - as const enum objects should include trailing commas")
+    public void generatesTrailingCommasInAsConstEnumObjectsAcrossTypeScriptGenerators() throws Exception {
+        final String specPath = "src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml";
+        List<String> generators = Arrays.asList(
+                "typescript-angular",
+                "typescript-axios",
+                "typescript-fetch",
+                "typescript-nestjs-server"
+        );
+
+        for (String generatorName : generators) {
+            File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+            output.deleteOnExit();
+
+            CodegenConfigurator configurator = new CodegenConfigurator()
+                    .setGeneratorName(generatorName)
+                    .setInputSpec(specPath)
+                    .setOutputDir(output.getAbsolutePath());
+
+            Generator generator = new DefaultGenerator();
+            generator.opts(configurator.toClientOptInput()).generate();
+
+            assertAsConstObjectsUseTrailingCommas(output.toPath(), generatorName);
+        }
+    }
+
     @Test(description = "Issue #22748 - Inner enums should not be double-prefixed when model has parent")
     public void givenChildModelWithInheritedInnerEnumThenEnumNameIsNotDoublePrefixed() throws Exception {
         // This tests that when a child model inherits from a parent that has an inner enum property,
@@ -310,4 +337,41 @@ public void givenChildModelWithInheritedInnerEnumThenEnumNameIsNotDoublePrefixed
                 "typescript-angular: Should contain 'Employee.ProjectRolesEnum' in " + modelFile);
     }
 
+    private void assertAsConstObjectsUseTrailingCommas(Path root, String generatorName) throws IOException {
+        final int[] asConstObjectCount = {0};
+
+        try (Stream<Path> paths = Files.walk(root)) {
+            paths.filter(Files::isRegularFile)
+                    .filter(path -> path.toString().endsWith(".ts"))
+                    .forEach(path -> {
+                        try {
+                            List<String> lines = Files.readAllLines(path);
+                            for (int i = 0; i < lines.size(); i++) {
+                                if (!lines.get(i).strip().equals("} as const;")) {
+                                    continue;
+                                }
+
+                                asConstObjectCount[0]++;
+
+                                int previousLineIndex = i - 1;
+                                while (previousLineIndex >= 0 && lines.get(previousLineIndex).isBlank()) {
+                                    previousLineIndex--;
+                                }
+
+                                Assert.assertTrue(
+                                        previousLineIndex >= 0 && lines.get(previousLineIndex).stripTrailing().endsWith(","),
+                                        generatorName + ": Expected trailing comma before '} as const;' in " + path);
+                            }
+                        } catch (IOException e) {
+                            throw new UncheckedIOException(e);
+                        }
+                    });
+        } catch (UncheckedIOException e) {
+            throw e.getCause();
+        }
+
+        Assert.assertTrue(asConstObjectCount[0] > 0,
+                generatorName + ": Expected generated as const enum objects");
+    }
+
 }

samples/client/others/typescript-angular-v20/builds/query-param-json/model/pageable.ts

@@ -33,7 +33,7 @@ export interface Pageable {
 export namespace Pageable {
     export const SortDirectionEnum = {
         Asc: 'ASC',
-        Desc: 'DESC'
+        Desc: 'DESC',
     } as const;
     export type SortDirectionEnum = typeof SortDirectionEnum[keyof typeof SortDirectionEnum];
 }

samples/client/others/typescript-fetch/infinite-recursion-issue/models/TestObjectType.ts

@@ -20,7 +20,7 @@
 export const TestObjectType = {
     TEST1: 'TEST1',
     TEST2: 'TEST2',
-    unknown_default_open_api: '11184809'
+    unknown_default_open_api: '11184809',
 } as const;
 export type TestObjectType = typeof TestObjectType[keyof typeof TestObjectType];