Output handlers

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handlePublicFiles

​

Signature

async function handlePublicFiles(
  publicFolder: string,
  vercelOutputDir: string,
  config: NextConfig
): Promise<void>

​

Parameters

​

Behavior

• Reads top-level items from the public folder
• Copies each item to {vercelOutputDir}/static/{basePath}/{item}
• Uses a semaphore to limit concurrent file operations to 16
• Silently continues if the public folder doesn’t exist

​

handleStaticOutputs

​

Signature

async function handleStaticOutputs(
  outputs: Array<AdapterOutput['STATIC_FILE']>,
  {
    config,
    vercelConfig,
    vercelOutputDir,
  }: {
    config: NextConfig;
    vercelConfig: VercelConfig;
    vercelOutputDir: string;
  }
): Promise<void>

​

Parameters

​

Behavior

• Copies static files to the output directory
• For HTML files: adds content-type override and path without extension
• Creates a not-found.txt file for 404 responses on _next/static resources
• Uses a semaphore to limit concurrent operations

​

Example

await handleStaticOutputs(outputs.staticFiles, {
  config,
  vercelConfig,
  vercelOutputDir,
});

// Creates:
// - .next/output/static/about.html -> served at /about
// - Adds to vercelConfig.overrides:
//   { "./about.html": { contentType: "text/html; charset=utf-8", path: "./about" } }

​

handleNodeOutputs

​

Signature

async function handleNodeOutputs(
  nodeOutputs: FuncOutputs,
  {
    config,
    distDir,
    repoRoot,
    projectDir,
    nextVersion,
    isMiddleware,
    prerenderFallbackFalseMap,
    vercelOutputDir,
  }: {
    config: NextConfig;
    distDir: string;
    repoRoot: string;
    projectDir: string;
    nextVersion: string;
    isMiddleware?: boolean;
    prerenderFallbackFalseMap: Record<string, string[]>;
    vercelOutputDir: string;
  }
): Promise<void>

​

Parameters

​

Behavior

1. Creates a .func directory for each function
2. Generates a launcher file (___next_launcher.cjs)
3. Creates a .vc-config.json with function configuration
4. Includes 404/error handlers in function assets
5. Supports workflow step and workflow configurations
6. Handles deterministic routes manifest

​

Function configuration

• runtime: Node.js runtime version
• handler: Path to launcher file
• filePathMap: All required files
• maxDuration: Execution timeout
• operationType: “PAGE” or “API”
• framework: { slug: "nextjs", version: "..." }
• supportsResponseStreaming: true
• useWebApi: true for middleware

​

handleEdgeOutputs

​

Signature

async function handleEdgeOutputs(
  edgeOutputs: FuncOutputs,
  {
    config,
    distDir,
    repoRoot,
    projectDir,
    nextVersion,
    vercelOutputDir,
  }: {
    distDir: string;
    config: NextConfig;
    repoRoot: string;
    projectDir: string;
    nextVersion: string;
    vercelOutputDir: string;
  }
): Promise<void>

​

Parameters

​

Behavior

1. Separates JavaScript and non-JavaScript assets
2. Generates Edge Function wrapper source
3. Handles WASM assets
4. Creates index.js entry point
5. Creates .vc-config.json with Edge Function configuration

​

Edge function configuration

• runtime: “edge”
• entrypoint: Path to index.js
• filePathMap: JS files
• assets: Non-JS files
• deploymentTarget: “v8-worker”
• environment: Environment variables
• regions: Deployment regions

​

handlePrerenderOutputs

​

Signature

async function handlePrerenderOutputs(
  prerenderOutputs: Array<AdapterOutput['PRERENDER']>,
  {
    config,
    hasAppEntries,
    vercelOutputDir,
    nodeOutputsParentMap,
    rscContentType,
    varyHeader,
  }: {
    hasAppEntries?: boolean;
    config: NextConfig;
    vercelOutputDir: string;
    nodeOutputsParentMap: Map<string, FuncOutputs[0]>;
    rscContentType: string;
    varyHeader: string;
  }
): Promise<void>

​

Parameters

​

Behavior

1. Creates symbolic links from prerender paths to parent functions
2. Generates .prerender-config.json files with ISR configuration
3. Handles fallback files with postponed state for PPR
4. Sets proper content-type headers for RSC and HTML
5. Configures revalidation and bypass tokens

​

Prerender configuration

• group: Revalidation group ID
• expiration: Revalidate time in seconds
• staleExpiration: Stale-while-revalidate time
• sourcePath: Path to parent function
• passQuery: true
• allowQuery: Allowed query parameters
• allowHeader: Allowed headers for cache variance
• bypassToken: ISR bypass token
• experimentalBypassFor: Bypass configuration
• initialHeaders: Headers from fallback
• initialStatus: Status code from fallback
• fallback: Path to fallback file
• chain: PPR chain configuration

​

handleMiddleware

​

Signature

async function handleMiddleware(
  output: AdapterOutput['MIDDLEWARE'],
  ctx: {
    config: NextConfig;
    nextVersion: string;
    distDir: string;
    repoRoot: string;
    projectDir: string;
    vercelOutputDir: string;
    prerenderFallbackFalseMap: Record<string, string[]>;
  }
): Promise<RouteWithSrc[]>

​

Parameters

​

Return value

• src: Source regex from matcher
• has/missing: Conditions
• middlewarePath: Path to middleware function
• middlewareRawSrc: Original source patterns
• continue: true
• override: true

​

Behavior

1. Delegates to handleNodeOutputs or handleEdgeOutputs based on runtime
2. Generates routes for each matcher in the middleware config
3. Routes include middleware path for execution

​

Example

const middlewareRoutes = await handleMiddleware(outputs.middleware, {
  config,
  nextVersion,
  distDir,
  repoRoot,
  projectDir,
  vercelOutputDir,
  prerenderFallbackFalseMap,
});

// Result:
// [
//   {
//     src: '^/api/.*',
//     middlewarePath: '/middleware',
//     middlewareRawSrc: ['/api/:path*'],
//     continue: true,
//     override: true
//   }
// ]