TypeScriptToLua · Perryvw · Nov 9, 2025 · Nov 9, 2025
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -42,7 +42,7 @@
         "node": ">=16.10.0"
     },
     "peerDependencies": {
-        "typescript": "5.8.2"
+        "typescript": "5.9.3"
     },
     "dependencies": {
         "@typescript-to-lua/language-extensions": "1.19.0",
@@ -69,7 +69,7 @@
         "prettier": "^2.8.8",
         "ts-jest": "^29.2.5",
         "ts-node": "^10.9.2",
-        "typescript": "5.8.2",
-        "typescript-eslint": "^8.26.0"
+        "typescript": "5.9.3",
+        "typescript-eslint": "^8.46.3"
     }
 }
diff --git a/src/lualib/SourceMapTraceBack.ts b/src/lualib/SourceMapTraceBack.ts
@@ -9,7 +9,6 @@ interface SourceMap {
 
 declare global {
     function __TS__originalTraceback(this: void, thread?: LuaThread, message?: string, level?: number): void;
-    // eslint-disable-next-line no-var
     var __TS__sourcemap: Record<string, SourceMap>;
 }
 

diff --git a/src/lualib/StringSplit.ts b/src/lualib/StringSplit.ts
@@ -1,9 +1,7 @@
 const sub = string.sub;
 const find = string.find;
 export function __TS__StringSplit(this: void, source: string, separator?: string, limit?: number): string[] {
-    if (limit === undefined) {
-        limit = 4294967295;
-    }
+    limit ??= 4294967295;
 
     if (limit === 0) {
         return [];

diff --git a/src/transformation/utils/scope.ts b/src/transformation/utils/scope.ts
@@ -60,9 +60,7 @@ export function markSymbolAsReferencedInCurrentScopes(
     identifier: ts.Identifier
 ): void {
     for (const scope of context.scopeStack) {
-        if (!scope.referencedSymbols) {
-            scope.referencedSymbols = new Map();
-        }
+        scope.referencedSymbols ??= new Map();
 
         const references = getOrUpdate(scope.referencedSymbols, symbolId, () => []);
         references.push(identifier);
@@ -87,9 +85,8 @@ export function findScope(context: TransformationContext, scopeTypes: ScopeType)
 }
 
 export function addScopeVariableDeclaration(scope: Scope, declaration: lua.VariableDeclarationStatement) {
-    if (!scope.variableDeclarations) {
-        scope.variableDeclarations = [];
-    }
+    scope.variableDeclarations ??= [];
+
     scope.variableDeclarations.push(declaration);
 }
 

diff --git a/src/transformation/visitors/class/index.ts b/src/transformation/visitors/class/index.ts
@@ -272,10 +272,8 @@ export const transformSuperExpression: FunctionVisitor<ts.SuperExpression> = (ex
         }
     }
 
-    if (!baseClassName) {
-        // Use "className.____super" if the base is not a simple identifier
-        baseClassName = lua.createTableIndexExpression(className, lua.createStringLiteral("____super"), expression);
-    }
+    // Use "className.____super" if the base is not a simple identifier
+    baseClassName ??= lua.createTableIndexExpression(className, lua.createStringLiteral("____super"), expression);
 
     const f = findFirstNodeAbove(expression, ts.isFunctionLike);
     if (f && ts.canHaveModifiers(f) && isStaticNode(f)) {

diff --git a/src/transformation/visitors/enum.ts b/src/transformation/visitors/enum.ts
@@ -60,9 +60,7 @@ export const transformEnumDeclaration: FunctionVisitor<ts.EnumDeclaration> = (no
                 }
             }
 
-            if (!valueExpression) {
-                valueExpression = context.transformExpression(member.initializer);
-            }
+            valueExpression ??= context.transformExpression(member.initializer);
         } else {
             valueExpression = lua.createNilLiteral();
         }

diff --git a/src/transformation/visitors/function.ts b/src/transformation/visitors/function.ts
@@ -343,9 +343,7 @@ export const transformFunctionDeclaration: FunctionVisitor<ts.FunctionDeclaratio
     // Remember symbols referenced in this function for hoisting later
     if (name.symbolId !== undefined) {
         const scope = peekScope(context);
-        if (!scope.functionDefinitions) {
-            scope.functionDefinitions = new Map();
-        }
+        scope.functionDefinitions ??= new Map();
 
         const functionInfo = { referencedSymbols: functionScope.referencedSymbols ?? new Map() };
         scope.functionDefinitions.set(name.symbolId, functionInfo);

diff --git a/src/transformation/visitors/modules/import.ts b/src/transformation/visitors/modules/import.ts
@@ -66,9 +66,7 @@ function transformImportSpecifier(
 export const transformImportDeclaration: FunctionVisitor<ts.ImportDeclaration> = (statement, context) => {
     const scope = peekScope(context);
 
-    if (!scope.importStatements) {
-        scope.importStatements = [];
-    }
+    scope.importStatements ??= [];
 
     const result: lua.Statement[] = [];
     const requireCall = createModuleRequire(context, statement.moduleSpecifier);