fix(npm): hide native CLI consoles on Windows

npm/cli/lib/child.js

@@ -1,7 +1,7 @@
 import { spawn } from "node:child_process";
 
 export async function runChild(command, args, options = {}) {
-  const child = spawn(command, args, { stdio: "inherit", ...options });
+  const child = spawn(command, args, { stdio: "inherit", windowsHide: true, ...options });
   const forward = (signal) => {
     if (!child.killed) {
       try {

npm/cli/lib/update.js

@@ -57,10 +57,10 @@ export async function updateNpmInstall({
   return { code: 0, signal: null };
 }
 
-function productionRunner() {
+export function productionRunner() {
   return {
     output(command, args) {
-      const result = spawnSync(command, args, { encoding: "utf8" });
+      const result = spawnSync(command, args, { encoding: "utf8", windowsHide: true });
       if (result.error) {
         throw result.error;
       }

npm/cli/package.json

@@ -15,7 +15,7 @@
     "LICENSE"
   ],
   "scripts": {
-    "test": "node --test test/*.test.mjs"
+    "test": "node --experimental-test-module-mocks --test test/*.test.mjs"
   },
   "engines": {
     "node": ">=22"

npm/cli/test/windows-hide.test.mjs

@@ -0,0 +1,53 @@
+import assert from "node:assert/strict";
+import { EventEmitter } from "node:events";
+import { mock, test } from "node:test";
+
+test("npm launcher hides native child consoles by default", async (t) => {
+  const spawnCalls = [];
+  const syncCalls = [];
+  mock.module("node:child_process", {
+    namedExports: {
+      spawn: (...args) => {
+        spawnCalls.push(args);
+        const child = new EventEmitter();
+        queueMicrotask(() => child.emit("exit", 0, null));
+        return child;
+      },
+      spawnSync: (...args) => {
+        syncCalls.push(args);
+        return { status: 0, stdout: "output", stderr: "" };
+      },
+    },
+  });
+  t.after(() => mock.restoreAll());
+
+  const { runChild } = await import("../lib/child.js?windows-hide-child");
+  const { productionRunner } = await import("../lib/update.js?windows-hide-update");
+
+  await runChild("mnemon", ["status"]);
+  const runner = productionRunner();
+  assert.equal(runner.output("npm", ["--version"]), "output");
+
+  assert.equal(spawnCalls[0][2].windowsHide, true);
+  assert.equal(syncCalls[0][2].windowsHide, true);
+});
+
+test("explicit child options can still override the default", async () => {
+  const spawnCalls = [];
+  mock.module("node:child_process", {
+    namedExports: {
+      spawn: (...args) => {
+        spawnCalls.push(args);
+        const child = new EventEmitter();
+        queueMicrotask(() => child.emit("exit", 0, null));
+        return child;
+      },
+      spawnSync: () => ({ status: 0, stdout: "", stderr: "" }),
+    },
+  });
+
+  const { runChild } = await import("../lib/child.js?windows-hide-override");
+  await runChild("mnemon", ["status"], { windowsHide: false });
+  assert.equal(spawnCalls[0][2].windowsHide, false);
+  mock.restoreAll();
+});