feat: emit runtime enum values as const arrays

Consumers need iterable enum values at runtime (e.g. for dropdown
options) but TypeScript union types are erased. Generate an enums.ts
file with `as const` arrays for each enum schema. Skip writing the
file when no enums exist.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: maxholman

lib/build.ts

@@ -21,15 +21,22 @@ export async function build(
    *
   */`.trim();
 
-	const { commandsFile, typesFile, mainFile, valibotFile, honoValibotFile } =
-		await processOpenApiDocument(outputDir, apischema.default, tags);
+	const {
+		commandsFile,
+		typesFile,
+		mainFile,
+		valibotFile,
+		honoValibotFile,
+		enumsFile,
+	} = await processOpenApiDocument(outputDir, apischema.default, tags);
 
 	const files = [
 		commandsFile,
 		typesFile,
 		mainFile,
 		valibotFile,
 		honoValibotFile,
+		...(enumsFile.getStatements().length > 0 ? [enumsFile] : []),
 	];
 
 	commandsFile.insertStatements(0, "/** eslint-disable max-classes */");

lib/process-document.ts

@@ -25,6 +25,7 @@ import {
 } from "./hono-valibot.ts";
 import { registerTypesFromSchema, schemaToType } from "./process-schema.ts";
 import {
+	camelCase,
 	castToValidJsIdentifier,
 	getDependents,
 	iife,
@@ -108,6 +109,13 @@ export async function processOpenApiDocument(
 		overwrite: true,
 	});
 
+	// Enums file for runtime enum values
+	const enumsFile = project.createSourceFile(
+		join(outputDir, "enums.ts"),
+		"",
+		{ overwrite: true },
+	);
+
 	// Validators file for Valibot schemas
 	const valibotFile = createValibotFile(project, outputDir);
 
@@ -243,6 +251,52 @@ export async function processOpenApiDocument(
 			schemaName,
 			schemaObject,
 		);
+
+		// Add enum values to enums file
+		if (
+			!("$ref" in schemaObject) &&
+			"enum" in schemaObject &&
+			Array.isArray(schemaObject.enum)
+		) {
+			const values = schemaObject.enum.filter(
+				(v): v is string => v !== null,
+			);
+
+			if (values.length > 0) {
+				enumsFile.addVariableStatement({
+					isExported: true,
+					declarationKind: VariableDeclarationKind.Const,
+					docs: schemaObject.description
+						? [
+								{
+									description: wordWrap(schemaObject.description),
+									tags: [
+										...(schemaObject.deprecated
+											? [{ tagName: "deprecated" }]
+											: []),
+									].filter(Boolean),
+								},
+							]
+						: [],
+					declarations: [
+						{
+							name: camelCase(schemaName),
+							initializer: Writers.assertion(
+								(writer) => {
+									writer.write("[");
+									values.forEach((value, index) => {
+										writer.write(JSON.stringify(value));
+										if (index < values.length - 1) writer.write(", ");
+									});
+									writer.write("]");
+								},
+								"const",
+							),
+						},
+					],
+				});
+			}
+		}
 	}
 
 	for (const [path, pathItemObject] of Object.entries<oas31.PathItemObject>(
@@ -1073,5 +1127,6 @@ export async function processOpenApiDocument(
 		mainFile,
 		valibotFile,
 		honoValibotFile,
+		enumsFile,
 	};
 }

lib/utils.ts

@@ -69,6 +69,10 @@ export function refToName(ref: string): string {
 	return name;
 }
 
+export function camelCase(...str: string[]): string {
+	return camelcase(str.flatMap((s) => s.split("/")));
+}
+
 export function pascalCase(...str: string[]): string {
 	return camelcase(
 		str.flatMap((s) => s.split("/")),