diff --git a/src/project/project.h b/src/project/project.h
--- a/src/project/project.h
+++ b/src/project/project.h
@@ -88,6 +88,16 @@
      */
     QList<KTextEditor::Document*> codeDocuments() const;
 
+    /**
+     * Creates a code document based on a given file path
+     */
+    KTextEditor::Document* createCodeDocument(const QString& filePath);
+
+    /**
+     * Returns a document of a given url (path)
+     */
+    KTextEditor::Document* openCodeDocument(const QUrl &url);
+
     /**
      * Add code document @p document to project. This updates the document's url.
      */
diff --git a/src/project/project.cpp b/src/project/project.cpp
--- a/src/project/project.cpp
+++ b/src/project/project.cpp
@@ -183,7 +183,6 @@
     d->m_graphEditor = graphEditor;
     d->m_projectUrl = projectFile;
     if (!d->loadProject(projectFile)) {
-        addCodeDocument(KTextEditor::Editor::instance()->createDocument(nullptr));
         addGraphDocument(graphEditor->createDocument());
         setModified(false);
         d->m_journal = KTextEditor::Editor::instance()->createDocument(nullptr);
@@ -222,26 +221,41 @@
     return d->m_workingDirectory.path();
 }
 
-bool Project::addCodeDocument(KTextEditor::Document *document)
+KTextEditor::Document* Project::createCodeDocument(const QString& filePath)
 {
-    // compute first unused document path
-    QStringList usedPaths;
-    foreach (KTextEditor::Document *document, d->m_codeDocuments) {
-        usedPaths.append(document->url().toLocalFile());
+    auto path = d->m_workingDirectory.path() + QLatin1Char('/') + filePath + QStringLiteral(".js");
+
+    auto doc = KTextEditor::Editor::instance()->createDocument(nullptr);
+    if (!doc->saveAs(QUrl::fromLocalFile(path))) {
+        qCritical() << "Error when saving code file to working directory, aborting.";
+        return nullptr;
     }
-    QString path;
-    for (int i = 0; i <= d->m_codeDocuments.count(); ++i) {
-        path = d->m_workingDirectory.path()
-            + QChar('/')
-            + "codefile" + QString::number(i) + QString(".js");
-        if (!usedPaths.contains(path)) {
-            break;
-        }
+
+    if (!addCodeDocument(doc)) {
+        return nullptr;
     }
 
-    // put document into working directory
-    if (!document->saveAs(QUrl::fromLocalFile(path))) {
-        qCritical() << "Error when saving code file to working directory, aborting.";
+    return doc;
+}
+
+KTextEditor::Document* Project::openCodeDocument(const QUrl &url)
+{
+    auto doc = KTextEditor::Editor::instance()->createDocument(nullptr);
+    if (!doc->openUrl(url)) {
+        qCritical() << "Error when opening code file, aborting.";
+        return nullptr;
+    }
+
+    if (!addCodeDocument(doc)) {
+        return nullptr;
+    }
+
+    return doc;
+}
+
+bool Project::addCodeDocument(KTextEditor::Document *document)
+{
+    if (document == nullptr) {
         return false;
     }
 
@@ -256,10 +270,7 @@
 
 KTextEditor::Document * Project::importCodeDocument(const QUrl &url)
 {
-    KTextEditor::Document *document = KTextEditor::Editor::instance()->createDocument(nullptr);
-    document->openUrl(url);
-    addCodeDocument(document);
-    return document;
+    return openCodeDocument(url);
 }
 
 void Project::tryToRemoveCodeDocument(KTextEditor::Document *document)
diff --git a/src/ui/mainwindow.h b/src/ui/mainwindow.h
--- a/src/ui/mainwindow.h
+++ b/src/ui/mainwindow.h
@@ -98,7 +98,7 @@
     void saveProjectAs();
 
     // script file handling
-    void createCodeDocument();
+    void tryToCreateCodeDocument();
     void importCodeDocument();
     void exportCodeDocument();
 
diff --git a/src/ui/mainwindow.cpp b/src/ui/mainwindow.cpp
--- a/src/ui/mainwindow.cpp
+++ b/src/ui/mainwindow.cpp
@@ -290,7 +290,7 @@
 
     createAction("document-save-as",     i18nc("@action:inmenu", "Save Project as"),   "save-project-as",    SLOT(saveProjectAs()), this);
     createAction("document-new",        i18nc("@action:inmenu", "New Graph Document"), "new-graph",         SLOT(createGraphDocument()), this);
-    createAction("document-new",        i18nc("@action:inmenu", "New Script File"),    "new-script",        SLOT(createCodeDocument()),    this);
+    createAction("document-new",        i18nc("@action:inmenu", "New Script File"),    "new-script",        SLOT(tryToCreateCodeDocument()),    this);
     createAction("document-import",     i18nc("@action:inmenu", "Import Graph"),       "import-graph",      SLOT(importGraphDocument()),   this);
     createAction("document-export",     i18nc("@action:inmenu", "Export Graph as"),    "export-graph-as",      SLOT(exportGraphDocument()), this);
     createAction("document-import",  i18nc("@action:inmenu", "Import Script"),       "add-script",          SLOT(importCodeDocument()),   this);
@@ -367,7 +367,7 @@
     }
 
     Project *project = new Project(m_graphEditor);
-    project->addCodeDocument(KTextEditor::Editor::instance()->createDocument(nullptr));
+    project->createCodeDocument(i18n("untitled"));
     project->addGraphDocument(m_graphEditor->createDocument());
     project->setModified(false);
 
@@ -480,18 +480,24 @@
     return targetFile.fileName();
 }
 
-void MainWindow::createCodeDocument()
+void MainWindow::tryToCreateCodeDocument()
 {
     QString basePrefix = QInputDialog::getText(this,
                             i18n("ScriptName"),
                             i18n("Enter the name of your new script"));
     if (basePrefix.isNull()) {
         qDebug() << "Filename is empty and no script file was created.";
-    } else {
-        QString fileName = uniqueFilename(basePrefix, "js"); //TODO this does nothing
-        KTextEditor::Document *document = KTextEditor::Editor::instance()->createDocument(nullptr);
-        m_currentProject->addCodeDocument(document);
+        return;
+    }
+
+    QString fullPath = m_currentProject->workingDir() + QLatin1Char('/') + basePrefix + QStringLiteral(".js");
+    QFileInfo file(fullPath);
+    if (file.exists()) {
+        KMessageBox::error(this, i18n("File already exists."));
+        return;
     }
+
+    m_currentProject->createCodeDocument(basePrefix);
 }
 
 void MainWindow::createGraphDocument()