MISC: Protect against reassigning certain globals (#972)

jest.config.js

@@ -10,12 +10,13 @@ module.exports = {
   moduleNameMapper: {
     "\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$":
       "<rootDir>/test/__mocks__/fileMock.js",
-    "\\.(css|less)$": "<rootDir>/test/__mocks__/styleMock.js",
-    "\\!!raw-loader!.*$": "<rootDir>/test/__mocks__/rawLoader.js",
+    "\\.(css|less)$": "<rootDir>/test/__mocks__/NullMock.js",
+    "\\!!raw-loader!.*$": "<rootDir>/test/__mocks__/NullMock.js",
     "@player": "<rootDir>/src/Player",
     "@enums": "<rootDir>/src/Enums",
     "@nsdefs": "<rootDir>/src/ScriptEditor/NetscriptDefinitions",
-    "^monaco-editor$": "<rootDir>/test/__mocks__/monacoMock.js",
-    "^monaco-vim$": "<rootDir>/test/__mocks__/monacoMock.js",
+    "^monaco-editor$": "<rootDir>/test/__mocks__/NullMock.js",
+    "^monaco-vim$": "<rootDir>/test/__mocks__/NullMock.js",
+    "/utils/Protections$": "<rootDir>/test/__mocks__/NullMock.js",
   },
 };

src/engine.tsx

@@ -9,6 +9,7 @@ import { staneksGift } from "./CotMG/Helper";
 import { processPassiveFactionRepGain, inviteToFaction } from "./Faction/FactionHelpers";
 import { Router } from "./ui/GameRoot";
 import { Page } from "./ui/Router";
+import "./utils/Protections"; // Side-effect: Protect against certain unrecoverable errors
 import "./PersonObjects/Player/PlayerObject"; // For side-effect of creating Player
 
 import {

src/utils/Protections.ts

@@ -0,0 +1,9 @@
+// This file is imported for side effects only.
+/* Prevent inadvertantly redefining certain window properties,
+   which are known to cause unrecoverable game errors when redefined.
+   The player is able to redefine these properties as writable if desired. */
+Object.defineProperties(window, {
+  Number: { writable: false },
+  Object: { writable: false },
+  String: { writable: false },
+});