TypeScriptToLua
diff --git a/‎src/Transpiler.ts‎
Lines changed: 6 additions & 1 deletion b/‎src/Transpiler.ts‎
Lines changed: 6 additions & 1 deletion
diff --git a/‎test/integration/lua/lualib.spec.ts‎
Lines changed: 31 additions & 0 deletions b/‎test/integration/lua/lualib.spec.ts‎
Lines changed: 31 additions & 0 deletions
@@ -757,7 +757,12 @@ export class LuaTranspiler {
             case "splice":
                 return `TS_splice(${caller}, ${params})`;
             case "join":
-                return `table.concat(${caller}, ${params})`;
+                if (node.arguments.length === 0) {
+                    // if seperator is omitted default seperator is ","
+                    return `table.concat(${caller}, ",")`;
+                } else {
+                    return `table.concat(${caller}, ${params})`;
+                }
             default:
                 throw new TranspileError("Unsupported array function: " + expression.name.escapedText, node);
         }
 
@@ -138,4 +138,35 @@ export class LuaLibArrayTests {
             Expect(result).toBe(JSON.stringify(inp.splice(start)));
         }
     }
+
+    @TestCase([], "")
+    @TestCase(["test1"], "test1")
+    @TestCase(["test1", "test2"], "test1,test2")
+    @TestCase(["test1", "test2"], "test1;test2", ";")
+    @TestCase(["test1", "test2"], "test1test2", "")
+    @Test("array.join")
+    public join<T>(inp: T[], expected: string, seperator?: string) {
+        let seperatorLua;
+        if (seperator === "") {
+            seperatorLua = "\"\"";
+        } else if (seperator) {
+            seperatorLua = "\"" + seperator + "\"";
+        } else {
+            seperatorLua = "";
+        }
+        // Transpile
+        let lua = util.transpileString(
+            `let joinTestTable = ${JSON.stringify(inp)};
+            return joinTestTable.join(${seperatorLua});`,
+            util.dummyTypes.Array
+        );
+
+        // Execute
+        let result = util.executeLua(lua);
+
+        // Assert
+        let joinedInp = inp.join(seperator);
+        Expect(result).toBe(joinedInp);
+    }
+
 }