From 66182c530d7142cf151d9667c79ffdb2a46b6548 Mon Sep 17 00:00:00 2001
From: Furkan <esquetta@gmail.com>
Date: Tue, 21 Jul 2026 10:39:40 +0300
Subject: [PATCH] fix: support npm 12 pack metadata

---
 src/core/npm-package-doctor.ts | 24 +++++++++++++++++++++---
 tests/npm-command.test.ts      | 20 ++++++++++++++++++++
 2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/src/core/npm-package-doctor.ts b/src/core/npm-package-doctor.ts
index 627776d..fe46d41 100644
--- a/src/core/npm-package-doctor.ts
+++ b/src/core/npm-package-doctor.ts
@@ -55,7 +55,7 @@ export interface BuildDoctorNpmPackageReportOptions {
   environment?: CompatibilityEnvironment;
 }
 
-interface NpmPackEntry {
+export interface NpmPackEntry {
   filename?: string;
   name?: string;
   version?: string;
@@ -66,6 +66,24 @@ interface NpmPackEntry {
   unpackedSize?: number;
 }
 
+export function parseNpmPackOutput(stdout: string): NpmPackEntry[] {
+  const parsed = JSON.parse(stdout) as unknown;
+
+  if (Array.isArray(parsed)) {
+    return parsed.filter(
+      (entry): entry is NpmPackEntry => typeof entry === "object" && entry !== null
+    );
+  }
+
+  if (typeof parsed === "object" && parsed !== null) {
+    return Object.values(parsed).filter(
+      (entry): entry is NpmPackEntry => typeof entry === "object" && entry !== null
+    );
+  }
+
+  return [];
+}
+
 interface CommandSpec {
   command: string;
   args: string[];
@@ -208,8 +226,8 @@ async function packNpmPackage(packageSpec: string, destinationPath: string): Pro
       maxBuffer: 10 * 1024 * 1024
     }
   );
-  const packEntries = JSON.parse(stdout) as NpmPackEntry[];
-  const metadata = packEntries[0];
+  const packEntries = parseNpmPackOutput(stdout);
+  const metadata = packEntries.find((entry) => typeof entry.filename === "string");
 
   if (!metadata?.filename) {
     throw new Error(`npm pack did not return a tarball for ${packageSpec}`);
diff --git a/tests/npm-command.test.ts b/tests/npm-command.test.ts
index 5e395e4..7727174 100644
--- a/tests/npm-command.test.ts
+++ b/tests/npm-command.test.ts
@@ -4,6 +4,7 @@ import path from "node:path";
 import { describe, expect, it } from "vitest";
 
 import { runCli } from "../src/run-cli.js";
+import { parseNpmPackOutput } from "../src/core/npm-package-doctor.js";
 
 function createIo() {
   const stdout: string[] = [];
@@ -87,6 +88,25 @@ async function createPackedPluginFixture(): Promise<string> {
 }
 
 describe("doctor npm command", () => {
+  it("normalizes npm pack JSON from npm 10 through npm 12", () => {
+    const entry = {
+      name: "doctor-npm-fixture",
+      version: "1.2.3",
+      filename: "doctor-npm-fixture-1.2.3.tgz"
+    };
+
+    expect(parseNpmPackOutput(JSON.stringify([entry]))).toEqual([entry]);
+    expect(
+      parseNpmPackOutput(JSON.stringify({ "doctor-npm-fixture": entry }))
+    ).toEqual([entry]);
+  });
+
+  it("rejects non-record npm pack JSON shapes", () => {
+    expect(parseNpmPackOutput("null")).toEqual([]);
+    expect(parseNpmPackOutput('"unexpected"')).toEqual([]);
+    expect(parseNpmPackOutput("[null, 1]")).toEqual([]);
+  });
+
   it("packs an npm package and reports preinstall plugin risk as JSON", async () => {
     const packageRoot = await createPackedPluginFixture();
     const { io, stdout, stderr } = createIo();