Adds insertbefore method on flex layout

src/cpp/core/FlexLayout/flexlayout.cpp

@@ -115,6 +115,27 @@ void FlexLayout::removeWidget(QWidget* childWidget, YGNodeRef childNode)
     QLayout::removeWidget(childWidget);
 }
 
+void FlexLayout::insertChildBefore(QWidget* childWidget, YGNodeRef beforeChildNode, YGNodeRef childNode)
+{
+    if(!this->node){
+        spdlog::warn("Flex layout's parent yoga node not set yet. Set it using setFlexNode. childwidget cant be inserted");
+        return;
+    }
+    uint count = YGNodeGetChildCount(this->node);
+    uint indexToInsert = 0;
+    for(uint i=0; i<count; i+=1){
+        if(beforeChildNode == YGNodeGetChild(this->node, i)){
+            indexToInsert = i;
+            break;
+        }
+    }
+    YGNodeInsertChild(this->node, childNode, indexToInsert);
+    QLayoutItem* layoutItem = new QWidgetItem(childWidget);
+    NodeContext* childContext = new NodeContext(layoutItem);
+    YGNodeSetContext(childNode, static_cast<void *>(childContext));
+    QLayout::addWidget(childWidget);
+}
+
 void FlexLayout::setGeometry(const QRect &rect)
 {
     if(!this->node){

src/cpp/core/FlexLayout/flexlayout.h

@@ -40,6 +40,7 @@ public:
     QLayoutItem *takeAt(int index) override;
     int count() const override;
     void addWidget(QWidget* childWidget, YGNodeRef childNode);
+    void insertChildBefore(QWidget* childWidget, YGNodeRef beforeChildNode, YGNodeRef childNode);
     void removeWidget(QWidget* childWidget, YGNodeRef childNode);
     void setGeometry(const QRect &rect) override;
     void setFlexNode(YGNodeRef parentNode);

src/cpp/core/FlexLayout/flexlayout_wrap.cpp

@@ -9,6 +9,7 @@ Napi::Object FlexLayoutWrap::init(Napi::Env env, Napi::Object exports) {
   char CLASSNAME[] = "FlexLayout";
   Napi::Function func = DefineClass(env, CLASSNAME, {
     InstanceMethod("addWidget", &FlexLayoutWrap::addWidget),
+    InstanceMethod("insertChildBefore", &FlexLayoutWrap::insertChildBefore),
     InstanceMethod("removeWidget", &FlexLayoutWrap::removeWidget),
     InstanceMethod("setFlexNode", &FlexLayoutWrap::setFlexNode),
   });
@@ -57,6 +58,22 @@ Napi::Value FlexLayoutWrap::addWidget(const Napi::CallbackInfo& info) {
   return env.Null();
 }
 
+Napi::Value FlexLayoutWrap::insertChildBefore(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+  Napi::HandleScope scope(env);
+
+  Napi::Object qwidgetObject = info[0].As<Napi::Object>();
+  Napi::External<YGNode> beforeChildFlexNodeObject = info[1].As<Napi::External<YGNode>>();
+  Napi::External<YGNode> childFlexNodeObject = info[2].As<Napi::External<YGNode>>();
+  QWidgetWrap* widget = Napi::ObjectWrap<QWidgetWrap>::Unwrap(qwidgetObject);
+  YGNodeRef childNodeRef = childFlexNodeObject.Data();
+  YGNodeRef beforeChildNodeRef = beforeChildFlexNodeObject.Data();
+
+  this->instance->insertChildBefore(widget->getInternalInstance(), beforeChildNodeRef, childNodeRef);
+  
+  return env.Null();
+}
+
 Napi::Value FlexLayoutWrap::removeWidget(const Napi::CallbackInfo& info) {
   Napi::Env env = info.Env();
   Napi::HandleScope scope(env);

src/cpp/core/FlexLayout/flexlayout_wrap.h

@@ -17,6 +17,7 @@ class FlexLayoutWrap : public  Napi::ObjectWrap<FlexLayoutWrap>{
   static Napi::FunctionReference constructor;
   //wrapped methods
   Napi::Value addWidget(const Napi::CallbackInfo& info);
+  Napi::Value insertChildBefore(const Napi::CallbackInfo& info);
   Napi::Value removeWidget(const Napi::CallbackInfo& info);
   Napi::Value setFlexNode(const Napi::CallbackInfo& info);
 };

src/lib/core/FlexLayout/index.ts

@@ -13,6 +13,24 @@ export class FlexLayout extends NodeLayout {
     this.children.add(childWidget);
     this.native.addWidget(childWidget.native, childYogaNode);
   };
+
+  insertChildBefore = (
+    childWidget: NodeWidget,
+    beforeChildWidget: NodeWidget,
+    childFlexNode?: FlexNode,
+    beforeChildFlexNode?: FlexNode
+  ) => {
+    const childYogaNode = childFlexNode || childWidget.getFlexNode();
+    const beforeChildYogaNode =
+      beforeChildFlexNode || beforeChildWidget.getFlexNode();
+    this.children.add(childWidget); // No orderer required yet, so just inserting at the end.
+    this.native.insertChildBefore(
+      childWidget.native,
+      beforeChildYogaNode,
+      childYogaNode
+    );
+  };
+
   removeWidget = (childWidget: NodeWidget, childFlexNode?: FlexNode) => {
     const childYogaNode = childFlexNode || childWidget.getFlexNode();
     this.native.removeWidget(childWidget.native, childYogaNode);