Enabled the @typescript-eslint/no-unused-expressions eslint rule (#2014)

## Description:

- Fixes #1790
- Fixed the codebase:
- expressions short-circuiting with `&&` changed to proper `if`
statements
  - `A instanceof B;` expressions now emit warnings

## Please complete the following:
- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:
michal7952

---------

Co-authored-by: Evan <evanpelle@gmail.com>

eslint.config.js

@@ -40,7 +40,6 @@ export default [
     rules: {
       // Disable rules that would fail. The failures should be fixed, and the entries here removed.
       "@typescript-eslint/no-explicit-any": "off",
-      "@typescript-eslint/no-unused-expressions": "off",
       "no-unused-vars": "off",
     },
   },

src/client/Main.ts

@@ -106,10 +106,9 @@ class Client {
     gameVersion.innerText = version;
 
     const newsModal = document.querySelector("news-modal") as NewsModal;
-    if (!newsModal) {
+    if (!newsModal || !(newsModal instanceof NewsModal)) {
       console.warn("News modal element not found");
     }
-    newsModal instanceof NewsModal;
     const newsButton = document.querySelector("news-button") as NewsButton;
     if (!newsButton) {
       console.warn("News button element not found");
@@ -168,7 +167,9 @@ class Client {
     const spModal = document.querySelector(
       "single-player-modal",
     ) as SinglePlayerModal;
-    spModal instanceof SinglePlayerModal;
+    if (!spModal || !(spModal instanceof SinglePlayerModal)) {
+      console.warn("Singleplayer modal element not found");
+    }
 
     const singlePlayer = document.getElementById("single-player");
     if (singlePlayer === null) throw new Error("Missing single-player");
@@ -185,7 +186,9 @@ class Client {
     // });
 
     const hlpModal = document.querySelector("help-modal") as HelpModal;
-    hlpModal instanceof HelpModal;
+    if (!hlpModal || !(hlpModal instanceof HelpModal)) {
+      console.warn("Help modal element not found");
+    }
     const helpButton = document.getElementById("help-button");
     if (helpButton === null) throw new Error("Missing help-button");
     helpButton.addEventListener("click", () => {
@@ -195,7 +198,10 @@ class Client {
     const flagInputModal = document.querySelector(
       "flag-input-modal",
     ) as FlagInputModal;
-    flagInputModal instanceof FlagInputModal;
+    if (!flagInputModal || !(flagInputModal instanceof FlagInputModal)) {
+      console.warn("Flag input modal element not found");
+    }
+
     const flgInput = document.getElementById("flag-input_");
     if (flgInput === null) throw new Error("Missing flag-input_");
     flgInput.addEventListener("click", () => {
@@ -205,6 +211,12 @@ class Client {
     this.patternsModal = document.querySelector(
       "territory-patterns-modal",
     ) as TerritoryPatternsModal;
+    if (
+      !this.patternsModal ||
+      !(this.patternsModal instanceof TerritoryPatternsModal)
+    ) {
+      console.warn("Territory patterns modal element not found");
+    }
     const patternButton = document.getElementById(
       "territory-patterns-input-preview-button",
     );
@@ -212,7 +224,12 @@ class Client {
       patternButton.style.display = "none";
     }
 
-    this.patternsModal instanceof TerritoryPatternsModal;
+    if (
+      !this.patternsModal ||
+      !(this.patternsModal instanceof TerritoryPatternsModal)
+    ) {
+      console.warn("Territory patterns modal element not found");
+    }
     if (patternButton === null)
       throw new Error("territory-patterns-input-preview-button");
     this.patternsModal.previewButton = patternButton;
@@ -224,7 +241,12 @@ class Client {
     this.tokenLoginModal = document.querySelector(
       "token-login",
     ) as TokenLoginModal;
-    this.tokenLoginModal instanceof TokenLoginModal;
+    if (
+      !this.tokenLoginModal ||
+      !(this.tokenLoginModal instanceof TokenLoginModal)
+    ) {
+      console.warn("Token login modal element not found");
+    }
 
     const onUserMe = async (userMeResponse: UserMeResponse | false) => {
       document.dispatchEvent(
@@ -335,7 +357,9 @@ class Client {
     const settingsModal = document.querySelector(
       "user-setting",
     ) as UserSettingModal;
-    settingsModal instanceof UserSettingModal;
+    if (!settingsModal || !(settingsModal instanceof UserSettingModal)) {
+      console.warn("User settings modal element not found");
+    }
     document
       .getElementById("settings-button")
       ?.addEventListener("click", () => {
@@ -345,7 +369,9 @@ class Client {
     const hostModal = document.querySelector(
       "host-lobby-modal",
     ) as HostPrivateLobbyModal;
-    hostModal instanceof HostPrivateLobbyModal;
+    if (!hostModal || !(hostModal instanceof HostPrivateLobbyModal)) {
+      console.warn("Host private lobby modal element not found");
+    }
     const hostLobbyButton = document.getElementById("host-lobby-button");
     if (hostLobbyButton === null) throw new Error("Missing host-lobby-button");
     hostLobbyButton.addEventListener("click", () => {
@@ -358,7 +384,9 @@ class Client {
     this.joinModal = document.querySelector(
       "join-private-lobby-modal",
     ) as JoinPrivateLobbyModal;
-    this.joinModal instanceof JoinPrivateLobbyModal;
+    if (!this.joinModal || !(this.joinModal instanceof JoinPrivateLobbyModal)) {
+      console.warn("Join private lobby modal element not found");
+    }
     const joinPrivateLobbyButton = document.getElementById(
       "join-private-lobby-button",
     );
@@ -573,8 +601,9 @@ class Client {
         const startingModal = document.querySelector(
           "game-starting-modal",
         ) as GameStartingModal;
-        startingModal instanceof GameStartingModal;
-        startingModal.show();
+        if (startingModal && startingModal instanceof GameStartingModal) {
+          startingModal.show();
+        }
       },
       () => {
         this.joinModal.close();

src/client/graphics/layers/EventsDisplay.ts

@@ -1051,7 +1051,7 @@ export class EventsDisplay extends LitElement implements Layer {
                                 ? this.renderButton({
                                     content: this.getEventDescription(event),
                                     onClick: () => {
-                                      event.focusID &&
+                                      if (event.focusID)
                                         this.emitGoToPlayerEvent(event.focusID);
                                     },
                                     className: "text-left",
@@ -1060,7 +1060,7 @@ export class EventsDisplay extends LitElement implements Layer {
                                   ? this.renderButton({
                                       content: this.getEventDescription(event),
                                       onClick: () => {
-                                        event.unitView &&
+                                        if (event.unitView)
                                           this.emitGoToUnitEvent(
                                             event.unitView,
                                           );

src/client/graphics/layers/StructureIconsLayer.ts

@@ -255,7 +255,9 @@ export class StructureIconsLayer implements Layer {
           this.potentialUpgrade.iconContainer.filters = [];
           this.potentialUpgrade.dotContainer.filters = [];
         }
-        this.ghostUnit?.container && (this.ghostUnit.container.filters = []);
+        if (this.ghostUnit?.container) {
+          this.ghostUnit.container.filters = [];
+        }
 
         if (!this.ghostUnit) return;
 

src/core/execution/RailroadExecution.ts

@@ -164,7 +164,7 @@ export class RailroadExecution implements Execution {
   }
 
   private redrawBuildings() {
-    this.railRoad.from.unit.isActive() && this.railRoad.from.unit.touch();
-    this.railRoad.to.unit.isActive() && this.railRoad.to.unit.touch();
+    if (this.railRoad.from.unit.isActive()) this.railRoad.from.unit.touch();
+    if (this.railRoad.to.unit.isActive()) this.railRoad.to.unit.touch();
   }
 }