feat: add type safety for builder configurations with discriminated unions

[pranaygp]

Improves type safety by creating discriminated union types for builder-specific
configurations, making it clear which configuration options are required for
each builder type.

Changes:

• Created BaseWorkflowConfig interface with common options
• Created StandaloneConfig, VercelBuildOutputConfig, and NextConfig types
• Made WorkflowConfig a discriminated union based on buildTarget
• Added documentation for each configuration type
• Exported new types from @workflow/builders

This enables better IntelliSense and type checking when constructing builder
configurations, preventing invalid configuration combinations at compile time.

🤖 Generated with Claude Code

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

[changeset-bot]

🦋 Changeset detected

Latest commit: 87c62d3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 7 packages

Name	Type
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/ai	Patch

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[pranaygp]

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• docs: add documentation and improve code clarity #84
• refactor: consolidate builder configuration patterns #83
• refactor: improve error handling in bundle creation #82
• refactor: extract path resolution and directory creation helpers #81
• feat: add type safety for builder configurations with discriminated unions #80 👈 (View in Graphite)
• refactor: standardize method naming and clarify log messages #79
• refactor: deduplicate package.json and .vc-config.json generation #77
• refactor: extract queue trigger configuration constants #76
• feat: move NextBuilder to @workflow/next package #74
• feat: create @workflow/builders package with shared builder infrastructure #73
• Rename vercel static builder to standalone builder #71
• main

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[vercel]

The isValidBuildTarget type guard function doesn't include the 'next' build target in its validation logic, but the new discriminated union WorkflowConfig now includes NextConfig with buildTarget: 'next'. This will cause type mismatches and incorrect validation.

View Details

📝 Patch Details

diff --git a/packages/builders/src/types.ts b/packages/builders/src/types.ts
index 8e2ae46..142d550 100644
--- a/packages/builders/src/types.ts
+++ b/packages/builders/src/types.ts
@@ -65,5 +65,5 @@ export type WorkflowConfig =
 export function isValidBuildTarget(
   target: string | undefined
 ): target is BuildTarget {
-  return target === 'standalone' || target === 'vercel-build-output-api';
+  return (validBuildTargets as readonly string[]).includes(target as string);
 }

Analysis

isValidBuildTarget() type guard doesn't validate 'next' build target

What fails: The isValidBuildTarget() type guard function in packages/builders/src/types.ts only validates 'standalone' and 'vercel-build-output-api' targets, but the BuildTarget type and validBuildTargets constant include 'next'. This causes the type guard to return false for a valid discriminant value that is part of the WorkflowConfig union type.

How to reproduce:

import { isValidBuildTarget, validBuildTargets, BuildTarget } from '@workflow/builders';

// validBuildTargets includes 'next'
console.log(validBuildTargets); // ['standalone', 'vercel-build-output-api', 'next']

// But the type guard rejects it
console.log(isValidBuildTarget('next')); // false (BUG)
console.log(isValidBuildTarget('standalone')); // true (works)
console.log(isValidBuildTarget('vercel-build-output-api')); // true (works)

Result: isValidBuildTarget('next') returns false, even though 'next' is:

1. In the validBuildTargets constant
2. A valid value for BuildTarget type
3. Part of the WorkflowConfig discriminated union via NextConfig

This causes type safety violations - code constructing a NextConfig with buildTarget: 'next' would fail validation with the type guard.

Expected: The type guard should return true for all three valid build targets, matching the BuildTarget type definition derived from validBuildTargets.

Fix: Changed the implementation to use the validBuildTargets constant for validation rather than hardcoded literals. This ensures any new build targets added to validBuildTargets are automatically validated, preventing future regressions.