From 28531c8987e27fc27fe39ff5db7a51e6c4cdc6b1 Mon Sep 17 00:00:00 2001
From: lolleko <larry.junglas@hotmail.de>
Date: Wed, 21 Feb 2018 19:10:00 +0100
Subject: [PATCH 1/2] Fixed concat if separator is omitted

---
 src/Transpiler.ts                   |  7 ++++++-
 test/integration/lua/lualib.spec.ts | 31 +++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/Transpiler.ts b/src/Transpiler.ts
index 3d9dc5499..b99872adf 100644
--- a/src/Transpiler.ts
+++ b/src/Transpiler.ts
@@ -741,7 +741,12 @@ export class LuaTranspiler {
             case "splice":
                 return `TS_splice(${caller}, ${params})`;
             case "join":
-                return `table.concat(${caller}, ${params})`;
+                if (!params) {
+                    // if seperator is omitted default seperator is ","
+                    return `table.concat(${caller}, ",")`;
+                } else {
+                    return `table.concat(${caller}, ${params})`;
+                }
             default:
                 throw new TranspileError("Unsupported array function: " + expression.name.escapedText, node);
         }
diff --git a/test/integration/lua/lualib.spec.ts b/test/integration/lua/lualib.spec.ts
index 57063709d..09f0d1b35 100644
--- a/test/integration/lua/lualib.spec.ts
+++ b/test/integration/lua/lualib.spec.ts
@@ -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);
+    }
+
 }

From 880ce9dc800a38107a4b0bb900cac5b6155374e0 Mon Sep 17 00:00:00 2001
From: lolleko <larry.junglas@hotmail.de>
Date: Wed, 21 Feb 2018 19:32:15 +0100
Subject: [PATCH 2/2] Updated condition

---
 src/Transpiler.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Transpiler.ts b/src/Transpiler.ts
index b99872adf..35dc40b74 100644
--- a/src/Transpiler.ts
+++ b/src/Transpiler.ts
@@ -741,7 +741,7 @@ export class LuaTranspiler {
             case "splice":
                 return `TS_splice(${caller}, ${params})`;
             case "join":
-                if (!params) {
+                if (node.arguments.length === 0) {
                     // if seperator is omitted default seperator is ","
                     return `table.concat(${caller}, ",")`;
                 } else {