Put update-notifier back.

Author: iclanton

apps/lockfile-explorer/package.json

@@ -52,6 +52,7 @@
     "@types/cors": "~2.8.12",
     "@types/express": "4.17.21",
     "@types/js-yaml": "4.0.9",
+    "@types/update-notifier": "~6.0.1",
     "eslint": "~9.37.0",
     "local-node-rig": "workspace:*",
     "@pnpm/lockfile.types": "1002.0.1",
@@ -69,7 +70,8 @@
     "cors": "~2.8.5",
     "express": "4.21.1",
     "js-yaml": "~4.1.0",
-    "semver": "~7.7.4"
+    "semver": "~7.7.4",
+    "update-notifier": "~5.1.0"
   },
   "exports": {
     "./lib/*.schema.json": "./lib-commonjs/*.schema.json",

apps/lockfile-explorer/src/cli/explorer/ExplorerCommandLineParser.ts

@@ -8,6 +8,7 @@ import type { ChildProcess } from 'node:child_process';
 import express from 'express';
 import yaml from 'js-yaml';
 import cors from 'cors';
+import updateNotifier from 'update-notifier';
 
 import {
   Executable,
@@ -85,6 +86,18 @@ export class ExplorerCommandLineParser extends CommandLineParser {
         Colorize.cyan(' - https://lfx.rushstack.io/\n')
     );
 
+    updateNotifier({
+      pkg: lockfileExplorerPackageJson,
+      // Normally update-notifier waits a day or so before it starts displaying upgrade notices.
+      // In debug mode, show the notice right away.
+      updateCheckInterval: this.isDebug ? 0 : undefined
+    }).notify({
+      // Make sure it says "-g" in the "npm install" example command line
+      isGlobal: true,
+      // Show the notice immediately, rather than waiting for process.onExit()
+      defer: false
+    });
+
     const PORT: number = 8091;
     // Must not have a trailing slash
     const SERVICE_URL: string = `http://localhost:${PORT}`;

common/changes/@rushstack/lockfile-explorer/dependency-cleanup_2026-04-17.json

@@ -2,7 +2,7 @@
   "changes": [
     {
       "packageName": "@rushstack/lockfile-explorer",
-      "comment": "Remove open and `update-notifier` dependencies; use `Executable.spawn()` from `node-core-library` to launch the browser.",
+      "comment": "Remove open dependency; use `Executable.spawn()` from `node-core-library` to launch the browser.",
       "type": "patch"
     }
   ],

common/config/rush/nonbrowser-approved-packages.json

@@ -1082,6 +1082,10 @@
       "name": "typescript",
       "allowedCategories": [ "libraries", "tests", "vscode-extensions" ]
     },
+    {
+      "name": "update-notifier",
+      "allowedCategories": [ "libraries" ]
+    },
     {
       "name": "url-loader",
       "allowedCategories": [ "libraries" ]