TypeScriptToLua · Perryvw · Feb 25, 2023 · Feb 25, 2023 · Feb 25, 2023
diff --git a/src/transformation/builtins/array.ts b/src/transformation/builtins/array.ts
@@ -94,14 +94,14 @@ export function transformArrayPrototypeCall(
             return transformLuaLibFunction(context, LuaLibFeature.ArrayEntries, node, caller);
         case "push":
             if (node.arguments.length === 1) {
-                const param = params[0];
+                const param = params[0] ?? lua.createNilLiteral();
                 if (isUnpackCall(param)) {
                     return transformLuaLibFunction(
                         context,
                         LuaLibFeature.ArrayPushArray,
                         node,
                         caller,
-                        (param as lua.CallExpression).params[0]
+                        (param as lua.CallExpression).params[0] ?? lua.createNilLiteral()
                     );
                 }
                 if (!lua.isDotsLiteral(param)) {
@@ -162,7 +162,7 @@ export function transformArrayPrototypeCall(
                 typeAlwaysHasSomeOfFlags(context, elementType, ts.TypeFlags.StringLike | ts.TypeFlags.NumberLike)
             ) {
                 const defaultSeparatorLiteral = lua.createStringLiteral(",");
-                const param = params[0];
+                const param = params[0] ?? lua.createNilLiteral();
                 const parameters = [
                     caller,
                     node.arguments.length === 0

diff --git a/src/transformation/builtins/math.ts b/src/transformation/builtins/math.ts
@@ -66,20 +66,33 @@ export function transformMathCall(
         case "log1p": {
             const log = lua.createStringLiteral("log");
             const one = lua.createNumericLiteral(1);
-            const add = lua.createBinaryExpression(one, params[0], lua.SyntaxKind.AdditionOperator);
+            const add = lua.createBinaryExpression(
+                one,
+                params[0] ?? lua.createNilLiteral(),
+                lua.SyntaxKind.AdditionOperator
+            );
             return lua.createCallExpression(lua.createTableIndexExpression(math, log), [add], node);
         }
 
         case "pow": {
             // Translate to base ^ power
-            return lua.createBinaryExpression(params[0], params[1], lua.SyntaxKind.PowerOperator, node);
+            return lua.createBinaryExpression(
+                params[0] ?? lua.createNilLiteral(),
+                params[1] ?? lua.createNilLiteral(),
+                lua.SyntaxKind.PowerOperator,
+                node
+            );
         }
 
         // math.floor(x + 0.5)
         case "round": {
             const floor = lua.createStringLiteral("floor");
             const half = lua.createNumericLiteral(0.5);
-            const add = lua.createBinaryExpression(params[0], half, lua.SyntaxKind.AdditionOperator);
+            const add = lua.createBinaryExpression(
+                params[0] ?? lua.createNilLiteral(),
+                half,
+                lua.SyntaxKind.AdditionOperator
+            );
             return lua.createCallExpression(lua.createTableIndexExpression(math, floor), [add], node);
         }
 

diff --git a/src/transformation/builtins/string.ts b/src/transformation/builtins/string.ts
@@ -42,7 +42,7 @@ export function transformStringPrototypeCall(
                 "find",
                 node,
                 caller,
-                params[0],
+                params[0] ?? lua.createNilLiteral(),
                 params[1]
                     ? // string.find handles negative indexes by making it relative to string end, but for indexOf it's the same as 0
                       lua.createCallExpression(
@@ -110,7 +110,7 @@ export function transformStringPrototypeCall(
             const literalValue = getNumberLiteralValue(params[0]);
             // Inline string.sub call if we know that parameter is pure and isn't negative
             if (literalValue !== undefined && literalValue >= 0) {
-                const firstParamPlusOne = addToNumericExpression(params[0], 1);
+                const firstParamPlusOne = addToNumericExpression(params[0] ?? lua.createNilLiteral(), 1);
                 return createStringCall("sub", node, caller, firstParamPlusOne, firstParamPlusOne);
             }
 
@@ -122,7 +122,12 @@ export function transformStringPrototypeCall(
             // Inline string.sub call if we know that parameter is pure and isn't negative
             if (literalValue !== undefined && literalValue >= 0) {
                 return lua.createBinaryExpression(
-                    createStringCall("byte", node, caller, addToNumericExpression(params[0], 1)),
+                    createStringCall(
+                        "byte",
+                        node,
+                        caller,
+                        addToNumericExpression(params[0] ?? lua.createNilLiteral(), 1)
+                    ),
                     createNaN(),
                     lua.SyntaxKind.OrOperator
                 );
@@ -140,7 +145,9 @@ export function transformStringPrototypeCall(
         case "repeat":
             const math = lua.createIdentifier("math");
             const floor = lua.createStringLiteral("floor");
-            const parameter = lua.createCallExpression(lua.createTableIndexExpression(math, floor), [params[0]]);
+            const parameter = lua.createCallExpression(lua.createTableIndexExpression(math, floor), [
+                params[0] ?? lua.createNilLiteral(),
+            ]);
             return createStringCall("rep", node, caller, parameter);
         case "padStart":
             return transformLuaLibFunction(context, LuaLibFeature.StringPadStart, node, caller, ...params);

diff --git a/src/transformation/utils/lua-ast.ts b/src/transformation/utils/lua-ast.ts
@@ -305,15 +305,17 @@ function getJSDocCommentFromTSNode(
     // https://stevedonovan.github.io/ldoc/manual/doc.md.html
     // LDoc comments require that the first line starts with three hyphens.
     // Thus, need to add a hyphen to the first line.
-    const firstLine = lines[0];
-    if (firstLine.startsWith(" @")) {
-        lines.unshift("-");
-    } else {
-        lines.shift();
-        lines.unshift("-" + firstLine);
-    }
+    if (lines.length > 0) {
+        const firstLine = lines[0];
+        if (firstLine.startsWith(" @")) {
+            lines.unshift("-");
+        } else {
+            lines.shift();
+            lines.unshift("-" + firstLine);
+        }
 
-    return lines;
+        return lines;
+    }
 }
 
 export const createNaN = (tsOriginal?: ts.Node) =>

diff --git a/test/unit/builtins/string.spec.ts b/test/unit/builtins/string.spec.ts
@@ -398,3 +398,15 @@ test.each(["string | undefined", "string | null", "null | string", "null | undef
             .expectToMatchJsResult();
     }
 );
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1406
+test("string.indexOf without arguments (#1406)", () => {
+    // Just test we do not throw here
+    util.testExpression`"".indexOf()`.expectToHaveDiagnostics();
+});
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1406
+test("string.repeat without arguments (#1406)", () => {
+    // Just test we do not throw here
+    util.testExpression`"".repeat()`.expectToHaveDiagnostics();
+});