[Code] Added and enforced no-fallthrough + added eslint type checking (#5705)

* Added and enforced `no-fallthrough`

* Fixed errors

* Fix package.json

* Moved vule to biom

* Fixed stuff

* Added workspace files to .gitignore for anyone who wants to do this stuff

* reverted accidental gitignore changes

* Update biome.jsonc

Co-authored-by: Sirz Benjie <142067137+SirzBenjie@users.noreply.github.com>

* Update biome.jsonc

Co-authored-by: Sirz Benjie <142067137+SirzBenjie@users.noreply.github.com>

* Update pokemon-species.ts

* Update biome.jsonc to apply reviews

* Fixed package.json

* Fix typo

---------

Co-authored-by: Sirz Benjie <142067137+SirzBenjie@users.noreply.github.com>
Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>

biome.jsonc

@@ -38,6 +38,9 @@
       "src/data/balance/tms.ts"
     ]
   },
+
+  // While it'd be nice to enable consistent sorting, enabling this causes issues due to circular import resolution order
+  // TODO: Remove if we ever get down to 0 circular imports
   "organizeImports": { "enabled": false },
   "linter": {
     "ignore": [
@@ -55,13 +58,13 @@
       },
       "style": {
         "noVar": "error",
-        "useEnumInitializers": "off",
+        "useEnumInitializers": "off", // large enums like Moves/Species would make this cumbersome 
         "useBlockStatements": "error",
         "useConst": "error",
         "useImportType": "error",
-        "noNonNullAssertion": "off", // TODO: Turn this on ASAP and fix all non-null assertions
+        "noNonNullAssertion": "off", // TODO: Turn this on ASAP and fix all non-null assertions in non-test files
         "noParameterAssign": "off",
-        "useExponentiationOperator": "off",
+        "useExponentiationOperator": "off", // Too typo-prone and easy to mixup with standard multiplication (* vs **)
         "useDefaultParameterLast": "off", // TODO: Fix spots in the codebase where this flag would be triggered, and then enable
         "useSingleVarDeclarator": "off",
         "useNodejsImportProtocol": "off",
@@ -70,17 +73,20 @@
       },
       "suspicious": {
         "noDoubleEquals": "error",
+        // While this would be a nice rule to enable, the current structure of the codebase makes this infeasible 
+        // due to being used for move/ability `args` params and save data-related code.
+        // This can likely be enabled for all non-utils files once these are eventually reworked, but until then we leave it off.  
         "noExplicitAny": "off",
         "noAssignInExpressions": "off",
         "noPrototypeBuiltins": "off",
-        "noFallthroughSwitchClause": "off",
-        "noImplicitAnyLet": "info", // TODO: Refactor and make this an error
-        "noRedeclare": "off", // TODO: Refactor and make this an error
+        "noFallthroughSwitchClause": "error", // Prevents accidental automatic fallthroughs in switch cases (use disable comment if needed)
+        "noImplicitAnyLet": "warn", // TODO: Refactor and make this an error
+        "noRedeclare": "info", // TODO: Refactor and make this an error
         "noGlobalIsNan": "off",
         "noAsyncPromiseExecutor": "warn" // TODO: Refactor and make this an error
       },
       "complexity": {
-        "noExcessiveCognitiveComplexity": "warn",
+        "noExcessiveCognitiveComplexity": "warn", // TODO: Refactor and make this an error
         "useLiteralKeys": "off",
         "noForEach": "off", // Foreach vs for of is not that simple.
         "noUselessSwitchCase": "off", // Explicit > Implicit

eslint.config.js

@@ -1,9 +1,10 @@
-import tseslint from "@typescript-eslint/eslint-plugin";
+/** @ts-check */
+import tseslint from "typescript-eslint";
 import stylisticTs from "@stylistic/eslint-plugin-ts";
 import parser from "@typescript-eslint/parser";
 import importX from "eslint-plugin-import-x";
 
-export default [
+export default tseslint.config(
   {
     name: "eslint-config",
     files: ["src/**/*.{ts,tsx,js,jsx}", "test/**/*.{ts,tsx,js,jsx}"],
@@ -14,12 +15,11 @@ export default [
     plugins: {
       "import-x": importX,
       "@stylistic/ts": stylisticTs,
-      "@typescript-eslint": tseslint,
+      "@typescript-eslint": tseslint.plugin,
     },
     rules: {
-      "prefer-const": "error", // Enforces the use of `const` for variables that are never reassigned
       "no-undef": "off", // Disables the rule that disallows the use of undeclared variables (TypeScript handles this)
-      "no-extra-semi": ["error"], // Disallows unnecessary semicolons for TypeScript-specific syntax
+      "no-extra-semi": "error", // Disallows unnecessary semicolons for TypeScript-specific syntax
       "import-x/extensions": ["error", "never", { json: "always" }], // Enforces no extension for imports unless json
     },
   },
@@ -33,11 +33,11 @@ export default [
       },
     },
     plugins: {
-      "@typescript-eslint": tseslint,
+      "@typescript-eslint": tseslint.plugin,
     },
     rules: {
       "@typescript-eslint/no-floating-promises": "error", // Require Promise-like statements to be handled appropriately. - https://typescript-eslint.io/rules/no-floating-promises/
       "@typescript-eslint/no-misused-promises": "error", // Disallow Promises in places not designed to handle them. - https://typescript-eslint.io/rules/no-misused-promises/
     },
   },
-];
+);

public/locales

@@ -1 +1 @@
-Subproject commit 18c1963ef309612a5a7fef76f9879709a7202189
+Subproject commit e98f0eb9c2022bc78b53f0444424c636498e725a

src/data/moves/move.ts

@@ -652,7 +652,7 @@ export default class Move implements Localizable {
         break;
       case MoveFlags.IGNORE_ABILITIES:
         if (user.hasAbilityWithAttr(MoveAbilityBypassAbAttr)) {
-          const abilityEffectsIgnored = new BooleanHolder(false); 
+          const abilityEffectsIgnored = new BooleanHolder(false);
           applyAbAttrs(MoveAbilityBypassAbAttr, user, abilityEffectsIgnored, false, this);
           if (abilityEffectsIgnored.value) {
             return true;
@@ -3160,7 +3160,7 @@ export class StatStageChangeAttr extends MoveEffectAttr {
   private get showMessage () {
     return this.options?.showMessage ?? true;
   }
-  
+
   /**
    * Attempts to change stats of the user or target (depending on value of selfTarget) if conditions are met
    * @param user {@linkcode Pokemon} the user of the move
@@ -6326,11 +6326,11 @@ export class ForceSwitchOutAttr extends MoveEffectAttr {
 
       if (!allyPokemon?.isActive(true) && switchOutTarget.hp) {
           globalScene.pushPhase(new BattleEndPhase(false));
-                    
+
           if (globalScene.gameMode.hasRandomBiomes || globalScene.isNewBiome()) {
             globalScene.pushPhase(new SelectBiomePhase());
           }
-          
+
           globalScene.pushPhase(new NewBattlePhase());
       }
     }

src/data/pokemon-species.ts

@@ -488,6 +488,7 @@ export abstract class PokemonSpeciesForm {
           if (formSpriteKey.startsWith("behemoth")) {
             formSpriteKey = "crowned";
           }
+          // biome-ignore lint/suspicious/no-fallthrough: Falls through
         default:
           ret += `-${formSpriteKey}`;
           break;

src/data/weather.ts

@@ -369,6 +369,7 @@ export function getRandomWeatherType(arena: Arena): WeatherType {
       if (hasSun) {
         weatherPool.push({ weatherType: WeatherType.SUNNY, weight: 2 });
       }
+      break;
     case Biome.VOLCANO:
       weatherPool = [
         {

src/system/settings/settings.ts

@@ -804,6 +804,7 @@ export function setSetting(setting: string, value: number): boolean {
       break;
     case SettingKeys.Candy_Upgrade_Display:
       globalScene.candyUpgradeDisplay = value;
+      break;
     case SettingKeys.Money_Format:
       switch (Setting[index].options[value].value) {
         case "Normal":

src/ui-inputs.ts

@@ -176,11 +176,13 @@ export class UiInputs {
       return;
     }
     switch (globalScene.ui?.getMode()) {
-      case UiMode.MESSAGE:
+      case UiMode.MESSAGE: {
         const messageHandler = globalScene.ui.getHandler<MessageUiHandler>();
         if (!messageHandler.pendingPrompt || messageHandler.isTextAnimationInProgress()) {
           return;
         }
+        // biome-ignore lint/suspicious/noFallthroughSwitchClause: falls through to show menu overlay
+      }
       case UiMode.TITLE:
       case UiMode.COMMAND:
       case UiMode.MODIFIER_SELECT:

tsconfig.json

@@ -7,7 +7,7 @@
     "esModuleInterop": true,
     "strictNullChecks": true,
     "sourceMap": false,
-    "strict": false,
+    "strict": false, // TODO: Enable this eventually
     "rootDir": ".",
     "baseUrl": "./src",
     "paths": {