diff --git a/scripts/ts/test.add.ts b/scripts/ts/test.add.ts
index e26f8d5..7295467 100644
--- a/scripts/ts/test.add.ts
+++ b/scripts/ts/test.add.ts
@@ -1,3 +1,5 @@
+import { type int } from "./type.aliases";
+
 class Test {
   public add(a: int, b: int): int {
     return a + b;
diff --git a/scripts/ts/test.sum.ts b/scripts/ts/test.sum.ts
index 9f8027b..0a6fb81 100644
--- a/scripts/ts/test.sum.ts
+++ b/scripts/ts/test.sum.ts
@@ -1,3 +1,5 @@
+import { type int } from "./type.aliases";
+
 function sum(n: int): int {
   let sum: int = 0;
   for (let i: int = 0; i < n; i++) {
diff --git a/scripts/ts/type.aliases.ts b/scripts/ts/type.aliases.ts
index 61b835c..91cc057 100644
--- a/scripts/ts/type.aliases.ts
+++ b/scripts/ts/type.aliases.ts
@@ -1 +1 @@
-type int = number;
+export type int = number;
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2Java.java b/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2Java.java
index 1f7817f..f3eba70 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2Java.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2Java.java
@@ -62,7 +62,7 @@ public String getTsCode() {
         return tsCode;
     }
 
-    public void transpile() throws Swc4jCoreException, Ts2JavaException {
+    public void transpile() throws Swc4jCoreException {
         classes.clear();
         Swc4jParseOutput output = swc4j.parse(getTsCode(), swc4jParseOptions);
         Swc4jAstScript script = (Swc4jAstScript) output.getProgram();
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2JavaException.java b/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2JavaException.java
index 3840517..cf2c602 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2JavaException.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/Ts2JavaException.java
@@ -16,7 +16,7 @@
 
 package com.caoccao.javet.buddy.ts2java;
 
-public class Ts2JavaException extends Exception {
+public class Ts2JavaException extends RuntimeException {
     public Ts2JavaException(String message) {
         super(message);
     }
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/BaseTs2JavaAst.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/BaseTs2JavaAst.java
index f005af1..9658e32 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/BaseTs2JavaAst.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/BaseTs2JavaAst.java
@@ -16,10 +16,9 @@
 
 package com.caoccao.javet.buddy.ts2java.ast;
 
-import com.caoccao.javet.buddy.ts2java.Ts2JavaException;
 import com.caoccao.javet.swc4j.ast.Swc4jAst;
 import net.bytebuddy.dynamic.DynamicType;
 
 public abstract class BaseTs2JavaAst<AST extends Swc4jAst> {
-    public abstract DynamicType.Builder<?> transpile(DynamicType.Builder<?> builder, AST ast) throws Ts2JavaException;
+    public abstract DynamicType.Builder<?> transpile(DynamicType.Builder<?> builder, AST ast);
 }
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstBindingIdent.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstBindingIdent.java
index 13673cc..8ae7c0e 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstBindingIdent.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstBindingIdent.java
@@ -29,6 +29,6 @@ public static Class<?> getClass(Swc4jAstBindingIdent ast) {
     }
 
     public static String getIdent(Swc4jAstBindingIdent ast) {
-        return ast.getId().getSym();
+        return Ts2JavaAstIdent.getSym(ast.getId());
     }
 }
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClass.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClass.java
index 132418d..5340b4e 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClass.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClass.java
@@ -16,7 +16,6 @@
 
 package com.caoccao.javet.buddy.ts2java.ast;
 
-import com.caoccao.javet.buddy.ts2java.Ts2JavaException;
 import com.caoccao.javet.swc4j.ast.clazz.Swc4jAstClass;
 import com.caoccao.javet.swc4j.ast.clazz.Swc4jAstClassMethod;
 import com.caoccao.javet.swc4j.ast.interfaces.ISwc4jAstClassMember;
@@ -26,8 +25,7 @@ public final class Ts2JavaAstClass extends BaseTs2JavaAst<Swc4jAstClass> {
     @Override
     public DynamicType.Builder<?> transpile(
             DynamicType.Builder<?> builder,
-            Swc4jAstClass ast)
-            throws Ts2JavaException {
+            Swc4jAstClass ast) {
         for (ISwc4jAstClassMember classMember : ast.getBody()) {
             switch (classMember.getType()) {
                 case ClassMethod:
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassDecl.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassDecl.java
index d8f0966..59467fe 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassDecl.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassDecl.java
@@ -16,7 +16,6 @@
 
 package com.caoccao.javet.buddy.ts2java.ast;
 
-import com.caoccao.javet.buddy.ts2java.Ts2JavaException;
 import com.caoccao.javet.swc4j.ast.stmt.Swc4jAstClassDecl;
 import com.caoccao.javet.utils.StringUtils;
 import net.bytebuddy.dynamic.DynamicType;
@@ -35,11 +34,10 @@ public String getPackageName() {
     @Override
     public DynamicType.Builder<?> transpile(
             DynamicType.Builder<?> builder,
-            Swc4jAstClassDecl ast)
-            throws Ts2JavaException {
+            Swc4jAstClassDecl ast) {
         String className = StringUtils.isEmpty(packageName)
-                ? ast.getIdent().getSym()
-                : packageName + "." + ast.getIdent().getSym();
+                ? Ts2JavaAstIdent.getSym(ast.getIdent())
+                : packageName + "." + Ts2JavaAstIdent.getSym(ast.getIdent());
         builder = builder.name(className);
         builder = new Ts2JavaAstClass().transpile(builder, ast.getClazz());
         return builder;
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassFunction.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassFunction.java
index 9402658..67b00eb 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassFunction.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassFunction.java
@@ -16,7 +16,6 @@
 
 package com.caoccao.javet.buddy.ts2java.ast;
 
-import com.caoccao.javet.buddy.ts2java.Ts2JavaException;
 import com.caoccao.javet.buddy.ts2java.compiler.JavaStackFrame;
 import com.caoccao.javet.buddy.ts2java.compiler.JavaStackObject;
 import com.caoccao.javet.swc4j.ast.clazz.Swc4jAstFunction;
@@ -25,10 +24,11 @@
 import net.bytebuddy.dynamic.DynamicType;
 import net.bytebuddy.implementation.MethodDelegation;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 import java.util.Stack;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 
 public final class Ts2JavaAstClassFunction extends BaseTs2JavaAst<Swc4jAstFunction> {
     private final Swc4jAstAccessibility accessibility;
@@ -50,19 +50,15 @@ public String getName() {
     @Override
     public DynamicType.Builder<?> transpile(
             DynamicType.Builder<?> builder,
-            Swc4jAstFunction ast)
-            throws Ts2JavaException {
+            Swc4jAstFunction ast) {
         final Visibility visibility = Ts2JavaAstAccessibility.getVisibility(accessibility);
         final Class<?> returnType = ast.getReturnType()
                 .map(Ts2JavaAstTsTypeAnn::getClass)
                 .orElse((Class) Object.class);
         final Stack<JavaStackFrame> stackFrames = new Stack<>();
-        final List<JavaStackObject> stackObjects = new ArrayList<>();
-        final int size = ast.getParams().size();
-        for (int i = 0; i < size; i++) {
-            JavaStackObject stackObject = Ts2JavaAstParam.getStackObject(i + 1, ast.getParams().get(i));
-            stackObjects.add(stackObject);
-        }
+        final List<JavaStackObject> stackObjects = IntStream.range(0, ast.getParams().size())
+                .mapToObj(i -> Ts2JavaAstParam.getStackObject(i + 1, ast.getParams().get(i)))
+                .collect(Collectors.toList());
         final JavaStackFrame stackFrame = new JavaStackFrame(stackObjects);
         stackFrames.push(stackFrame);
         final Class<?>[] parameters = stackFrame.getObjects().stream()
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassMethod.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassMethod.java
index f78bc4d..773b71d 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassMethod.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstClassMethod.java
@@ -27,8 +27,7 @@ public final class Ts2JavaAstClassMethod extends BaseTs2JavaAst<Swc4jAstClassMet
     @Override
     public DynamicType.Builder<?> transpile(
             DynamicType.Builder<?> builder,
-            Swc4jAstClassMethod ast)
-            throws Ts2JavaException {
+            Swc4jAstClassMethod ast) {
         if (ast.isStatic()) {
             throw new Ts2JavaException("Not implemented");
         }
@@ -38,7 +37,7 @@ public DynamicType.Builder<?> transpile(
         if (!(ast.getKey() instanceof Swc4jAstIdentName)) {
             throw new Ts2JavaException("Function ident type " + ast.getKey().getClass().getSimpleName() + " is not supported");
         }
-        String name = ast.getKey().as(Swc4jAstIdentName.class).getSym();
+        String name = Ts2JavaAstIdentName.getSym(ast.getKey().as(Swc4jAstIdentName.class));
         Swc4jAstAccessibility accessibility = ast.getAccessibility().orElse(Swc4jAstAccessibility.Public);
         builder = new Ts2JavaAstClassFunction(name, accessibility).transpile(builder, ast.getFunction());
         return builder;
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdent.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdent.java
new file mode 100644
index 0000000..798e872
--- /dev/null
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdent.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2024-2024. caoccao.com Sam Cao
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.caoccao.javet.buddy.ts2java.ast;
+
+import com.caoccao.javet.swc4j.ast.expr.Swc4jAstIdent;
+
+public final class Ts2JavaAstIdent {
+    private Ts2JavaAstIdent() {
+    }
+
+    public static String getSym(Swc4jAstIdent ast) {
+        return ast.getSym();
+    }
+}
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdentName.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdentName.java
new file mode 100644
index 0000000..609ad2b
--- /dev/null
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstIdentName.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2024-2024. caoccao.com Sam Cao
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.caoccao.javet.buddy.ts2java.ast;
+
+import com.caoccao.javet.swc4j.ast.expr.Swc4jAstIdentName;
+
+public final class Ts2JavaAstIdentName {
+    private Ts2JavaAstIdentName() {
+    }
+
+    public static String getSym(Swc4jAstIdentName ast) {
+        return ast.getSym();
+    }
+}
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstParam.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstParam.java
index 77d81d2..41e44f3 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstParam.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstParam.java
@@ -25,7 +25,7 @@ public final class Ts2JavaAstParam {
     private Ts2JavaAstParam() {
     }
 
-    public static JavaStackObject getStackObject(int index, Swc4jAstParam ast) throws Ts2JavaException {
+    public static JavaStackObject getStackObject(int index, Swc4jAstParam ast) {
         switch (ast.getPat().getType()) {
             case BindingIdent:
                 String ident = Ts2JavaAstBindingIdent.getIdent(ast.getPat().as(Swc4jAstBindingIdent.class));
diff --git a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstTsEntityName.java b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstTsEntityName.java
index c0c6688..7fc4d97 100644
--- a/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstTsEntityName.java
+++ b/src/main/java/com/caoccao/javet/buddy/ts2java/ast/Ts2JavaAstTsEntityName.java
@@ -26,8 +26,7 @@ private Ts2JavaAstTsEntityName() {
     public static String getName(ISwc4jAstTsEntityName ast) {
         switch (ast.getType()) {
             case Ident:
-                Swc4jAstIdent ident = ast.as(Swc4jAstIdent.class);
-                return ident.getSym();
+                return Ts2JavaAstIdent.getSym(ast.as(Swc4jAstIdent.class));
             default:
                 return null;
         }