import { relative } from 'node:path'; import { transform } from '@swc/core'; type DecoratorOptions = import('@workflow/builders').DecoratorOptions; type WorkflowPatternMatch = import('@workflow/builders').WorkflowPatternMatch; // Cache decorator options per working directory to avoid reading tsconfig for every file const decoratorOptionsCache = new Map>(); // Cache for shared utilities from @workflow/builders (ESM module loaded dynamically in CommonJS context) let cachedBuildersModule: typeof import('@workflow/builders') | null = null; async function getBuildersModule(): Promise< typeof import('@workflow/builders') > { if (cachedBuildersModule) { return cachedBuildersModule; } // Dynamic import to handle ESM module from CommonJS context // biome-ignore lint/security/noGlobalEval: Need to use eval here to avoid TypeScript from transpiling the import statement into `require()` cachedBuildersModule = (await eval( 'import("@workflow/builders")' )) as typeof import('@workflow/builders'); return cachedBuildersModule; } async function getDecoratorOptions( workingDir: string ): Promise { const cached = decoratorOptionsCache.get(workingDir); if (cached) { return cached; } const promise = (async (): Promise => { const { getDecoratorOptionsForDirectory } = await getBuildersModule(); return getDecoratorOptionsForDirectory(workingDir); })(); decoratorOptionsCache.set(workingDir, promise); return promise; } async function detectPatterns(source: string): Promise { const { detectWorkflowPatterns } = await getBuildersModule(); return detectWorkflowPatterns(source); } async function checkGeneratedFile(filePath: string): Promise { const { isGeneratedWorkflowFile } = await getBuildersModule(); return isGeneratedWorkflowFile(filePath); } async function checkSdkFile(filePath: string): Promise { const { isWorkflowSdkFile } = await getBuildersModule(); return isWorkflowSdkFile(filePath); } async function checkShouldTransform( filePath: string, patterns: WorkflowPatternMatch ): Promise { const { shouldTransformFile } = await getBuildersModule(); return shouldTransformFile(filePath, patterns); } // This loader applies the "use workflow"/"use step" // client transformation export default async function workflowLoader( this: { resourcePath: string; }, source: string | Buffer, sourceMap: any ): Promise { const filename = this.resourcePath; const normalizedSource = source.toString(); // Skip generated workflow route files to avoid re-processing them if (await checkGeneratedFile(filename)) { return normalizedSource; } // Detect workflow patterns in the source code const patterns = await detectPatterns(normalizedSource); // For @workflow SDK packages, only transform files with actual directives, // not files that just match serde patterns (which are internal SDK implementation files) const isSdkFile = await checkSdkFile(filename); if (isSdkFile && !patterns.hasDirective) { return normalizedSource; } // Check if file needs transformation based on patterns and path if (!(await checkShouldTransform(filename, patterns))) { return normalizedSource; } const isTypeScript = filename.endsWith('.ts') || filename.endsWith('.tsx') || filename.endsWith('.mts') || filename.endsWith('.cts'); // Calculate relative filename for SWC plugin // The SWC plugin uses filename to generate workflowId, so it must be relative const workingDir = process.cwd(); const normalizedWorkingDir = workingDir .replace(/\\/g, '/') .replace(/\/$/, ''); const normalizedFilepath = filename.replace(/\\/g, '/'); // Windows fix: Use case-insensitive comparison to work around drive letter casing issues const lowerWd = normalizedWorkingDir.toLowerCase(); const lowerPath = normalizedFilepath.toLowerCase(); let relativeFilename: string; if (lowerPath.startsWith(lowerWd + '/')) { // File is under working directory - manually calculate relative path relativeFilename = normalizedFilepath.substring( normalizedWorkingDir.length + 1 ); } else if (lowerPath === lowerWd) { // File IS the working directory (shouldn't happen) relativeFilename = '.'; } else { // Use relative() for files outside working directory relativeFilename = relative(workingDir, filename).replace(/\\/g, '/'); if (relativeFilename.startsWith('../')) { relativeFilename = relativeFilename .split('/') .filter((part) => part !== '..') .join('/'); } } // Final safety check - ensure we never pass an absolute path to SWC if (relativeFilename.includes(':') || relativeFilename.startsWith('/')) { // This should rarely happen, but use filename split as last resort relativeFilename = normalizedFilepath.split('/').pop() || 'unknown.ts'; } // Get decorator options from tsconfig (cached per working directory) const decoratorOptions = await getDecoratorOptions(workingDir); // Transform with SWC const result = await transform(normalizedSource, { filename: relativeFilename, jsc: { parser: { ...(isTypeScript ? { syntax: 'typescript', tsx: filename.endsWith('.tsx'), decorators: decoratorOptions.decorators, } : { syntax: 'ecmascript', jsx: filename.endsWith('.jsx'), decorators: decoratorOptions.decorators, }), }, target: 'es2022', experimental: { plugins: [ [require.resolve('@workflow/swc-plugin'), { mode: 'client' }], ], }, transform: { react: { runtime: 'preserve', }, legacyDecorator: decoratorOptions.legacyDecorator, decoratorMetadata: decoratorOptions.decoratorMetadata, }, }, minify: false, inputSourceMap: sourceMap, sourceMaps: true, inlineSourcesContent: true, }); return result.code; }