Status Manifest (status-manifest.js)

💡 Overview

During application execution, the Express routing server needs to know whether a requested route is compiled successfully (status 200), has triggered a redirect (status 302), or is missing.

The status-manifest.js utility provides a lightweight, in-memory registry (statusMap) to track the HTTP status codes generated during the static rendering passes of all pages.

📊 Manifest API Structure

The chart below traces the simple, high-performance key-value operations exposed by the manifest:

⚡ Role in the Server Lifecycle

Although simple, the Status Manifest performs key optimization work during route resolution:

• Bypass Read Overhead: Instead of parsing metadata.json files from disk on every page view to check compile states, the main Express router queries getStatus(), reducing file system I/O bounds.
• Mutations Checking: When background ISR or dynamic ISG compiles routes, they invoke updateStatus(path, status). If the new status matches the cached code, the operation exits immediately to avoid triggering HMR reload notifications.

⚙️ Complete Code Walkthrough

Below is the full, complete code of status-manifest.js:

const statusMap = new Map(); // In-memory compilation status registry

function getStatus(reqPath) {
  return statusMap.get(reqPath)?.status;
}

function updateStatus(reqPath, status) {
  const current = statusMap.get(reqPath)?.status;
  if (current === status) return; // Prevent unnecessary map updates

  statusMap.set(reqPath, { status });
}

module.exports = { getStatus, updateStatus };