refactor: consolidate builder configuration patterns

Extracts common builder configuration pattern into a reusable helper function,
improving consistency across framework integrations.

Changes:
- Created createBaseBuilderConfig() helper in @workflow/builders
- Updated @workflow/nitro builders to use the new helper
- Removed CommonBuildOptions constant from nitro package
- Added clear documentation for when bundle paths are not used

This makes it easier for framework integrations to create properly configured
builder instances without manually specifying unused bundle path properties.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: 2 people

.changeset/consolidate-config.md

@@ -0,0 +1,6 @@
+---
+"@workflow/builders": patch
+"@workflow/nitro": patch
+---
+
+Consolidate builder configuration patterns

packages/builders/src/config-helpers.ts

@@ -0,0 +1,22 @@
+import type { WorkflowConfig } from './types.js';
+
+/**
+ * Creates a partial configuration for builders that don't use bundle paths directly.
+ * Used by framework integrations like Nitro where the builder computes paths internally.
+ */
+export function createBaseBuilderConfig(options: {
+  workingDir: string;
+  dirs?: string[];
+  watch?: boolean;
+  externalPackages?: string[];
+}): Omit<WorkflowConfig, 'buildTarget'> {
+  return {
+    dirs: options.dirs ?? ['workflows'],
+    workingDir: options.workingDir,
+    watch: options.watch,
+    stepsBundlePath: '', // Not used by base builder methods
+    workflowsBundlePath: '', // Not used by base builder methods
+    webhookBundlePath: '', // Not used by base builder methods
+    externalPackages: options.externalPackages,
+  };
+}

packages/builders/src/index.ts

@@ -1,6 +1,7 @@
 export type { WorkflowManifest } from './apply-swc-transform.js';
 export { applySwcTransform } from './apply-swc-transform.js';
 export { BaseBuilder } from './base-builder.js';
+export { createBaseBuilderConfig } from './config-helpers.js';
 export { STEP_QUEUE_TRIGGER, WORKFLOW_QUEUE_TRIGGER } from './constants.js';
 export { createDiscoverEntriesPlugin } from './discover-entries-esbuild-plugin.js';
 export { createNodeModuleErrorPlugin } from './node-module-esbuild-plugin.js';

packages/nitro/src/builders.ts

@@ -1,21 +1,19 @@
 import { mkdir, readFile, writeFile } from 'node:fs/promises';
-import { BaseBuilder, VercelBuildOutputAPIBuilder } from '@workflow/builders';
+import {
+  BaseBuilder,
+  VercelBuildOutputAPIBuilder,
+  createBaseBuilderConfig,
+} from '@workflow/builders';
 import type { Nitro } from 'nitro/types';
 import { join, resolve } from 'pathe';
 
-const CommonBuildOptions = {
-  buildTarget: 'next' as const, // unused in base
-  stepsBundlePath: '', // unused in base
-  workflowsBundlePath: '', // unused in base
-  webhookBundlePath: '', // unused in base
-};
-
 export class VercelBuilder extends VercelBuildOutputAPIBuilder {
   constructor(nitro: Nitro) {
     super({
-      ...CommonBuildOptions,
-      dirs: getWorkflowDirs(nitro),
-      workingDir: nitro.options.rootDir,
+      ...createBaseBuilderConfig({
+        workingDir: nitro.options.rootDir,
+      }),
+      buildTarget: 'vercel-build-output-api',
     });
   }
   override async build(): Promise<void> {
@@ -36,10 +34,11 @@ export class LocalBuilder extends BaseBuilder {
   constructor(nitro: Nitro) {
     const outDir = join(nitro.options.buildDir, 'workflow');
     super({
-      ...CommonBuildOptions,
-      dirs: getWorkflowDirs(nitro),
-      workingDir: nitro.options.rootDir,
-      watch: nitro.options.dev,
+      ...createBaseBuilderConfig({
+        workingDir: nitro.options.rootDir,
+        watch: nitro.options.dev,
+      }),
+      buildTarget: 'next', // Placeholder, not actually used
     });
     this.#outDir = outDir;
   }