diff --git a/src/litegraph.d.ts b/src/litegraph.d.ts
index 4f2a875d4..9d3d37c02 100644
--- a/src/litegraph.d.ts
+++ b/src/litegraph.d.ts
@@ -740,7 +740,7 @@ export declare class LGraphNode {
         name: string,
         type: string | -1,
         extra_info?: Partial<INodeOutputSlot>
-    ): void;
+    ): INodeOutputSlot;
     /**
      * add a new output slot to use in this node
      * @param array of triplets like [[name,type,extra_info],[...]]
@@ -760,7 +760,7 @@ export declare class LGraphNode {
         name: string,
         type: string | -1,
         extra_info?: Partial<INodeInputSlot>
-    ): void;
+    ): INodeInputSlot;
     /**
      * add several new input slots in this node
      * @param array of triplets like [[name,type,extra_info],[...]]
@@ -953,13 +953,34 @@ export declare class LGraphNode {
     /**
      * if returns false the incoming connection will be canceled
      * Called by `LGraph.connect`
+     * @param inputIndex target input slot number
+     * @param outputType type of output slot
+     * @param outputSlot output slot object
+     * @param outputNode node containing the output
+     * @param outputIndex index of output slot
      */
     onConnectInput?(
         inputIndex: number,
-        type: INodeOutputSlot["type"],
+        outputType: INodeOutputSlot["type"],
         outputSlot: INodeOutputSlot,
-        _this: this,
-        slotIndex: number
+        outputNode: LGraphNode,
+        outputIndex: number
+    ): boolean;
+    /**
+     * if returns false the incoming connection will be canceled
+     * Called by `LGraph.connect`
+     * @param outputIndex target output slot number
+     * @param inputType type of input slot
+     * @param inputSlot input slot object
+     * @param inputNode node containing the input
+     * @param inputIndex index of input slot
+     */
+    onConnectOutput?(
+        outputIndex: number,
+        inputType: INodeInputSlot["type"],
+        inputSlot: INodeInputSlot,
+        inputNode: LGraphNode,
+        inputIndex: number
     ): boolean;
 
     /**
diff --git a/src/litegraph.js b/src/litegraph.js
index 7b9557a18..b14851357 100755
--- a/src/litegraph.js
+++ b/src/litegraph.js
@@ -3685,99 +3685,94 @@
         }
 
 		var changed = false;
-
-        //if there is something already plugged there, disconnect
-        if (target_node.inputs[target_slot].link != null) {
-			this.graph.beforeChange();
-            target_node.disconnectInput(target_slot);
-			changed = true;
-        }
-
-        //why here??
-        //this.setDirtyCanvas(false,true);
-        //this.graph.connectionChange( this );
-
-        var output = this.outputs[slot];
-
-        //allows nodes to block connection
-        if (target_node.onConnectInput) {
-            if ( target_node.onConnectInput(target_slot, output.type, output, this, slot) === false ) {
-                return null;
-            }
-        }
-
         var input = target_node.inputs[target_slot];
+        var output = this.outputs[slot];
         var link_info = null;
 
-		//this slots cannot be connected (different types)
-        if (!LiteGraph.isValidConnection(output.type, input.type))
-		{
-	        this.setDirtyCanvas(false, true);
-			if(changed)
-		        this.graph.connectionChange(this, link_info);
-			return null;
-		}
+        if (LiteGraph.isValidConnection(output.type, input.type)) {
+            if (target_node.onBeforeConnectInput) {
+                // This way node can choose another slot (if selected is occupied)
+                target_slot = target_node.onBeforeConnectInput(target_slot);
+            }
 
-		if(!changed)
-			this.graph.beforeChange();
+            //if there is something already plugged there, disconnect
+            if (target_node.inputs[target_slot].link != null) {
+                target_node.disconnectInput(target_slot);
+            }
 
-		//create link class
-		link_info = new LLink(
-			++this.graph.last_link_id,
-			input.type,
-			this.id,
-			slot,
-			target_node.id,
-			target_slot
-		);
+            //why here??
+            //this.setDirtyCanvas(false,true);
+            //this.graph.connectionChange( this );
 
-		//add to graph links list
-		this.graph.links[link_info.id] = link_info;
+            //allows nodes to block connection
+            if (target_node.onConnectInput) {
+                if ( target_node.onConnectInput(target_slot, output.type, output, this, slot) === false ) {
+                    return null;
+                }
+            }
+            if (this.onConnectOutput) {
+                if ( this.onConnectOutput(slot, input.type, input, target_node, target_slot) === false ) {
+                    return null;
+                }
+            }
 
-		//connect in output
-		if (output.links == null) {
-			output.links = [];
-		}
-		output.links.push(link_info.id);
-		//connect in input
-		target_node.inputs[target_slot].link = link_info.id;
-		if (this.graph) {
-			this.graph._version++;
-		}
-		if (this.onConnectionsChange) {
-			this.onConnectionsChange(
-				LiteGraph.OUTPUT,
-				slot,
-				true,
-				link_info,
-				output
-			);
-		} //link_info has been created now, so its updated
-		if (target_node.onConnectionsChange) {
-			target_node.onConnectionsChange(
-				LiteGraph.INPUT,
-				target_slot,
-				true,
-				link_info,
-				input
-			);
-		}
-		if (this.graph && this.graph.onNodeConnectionChange) {
-			this.graph.onNodeConnectionChange(
-				LiteGraph.INPUT,
-				target_node,
-				target_slot,
-				this,
-				slot
-			);
-			this.graph.onNodeConnectionChange(
-				LiteGraph.OUTPUT,
-				this,
-				slot,
-				target_node,
-				target_slot
-			);
-		}
+            link_info = new LLink(
+                ++this.graph.last_link_id,
+                input.type,
+                this.id,
+                slot,
+                target_node.id,
+                target_slot
+            );
+
+            //add to graph links list
+            this.graph.links[link_info.id] = link_info;
+
+            //connect in output
+            if (output.links == null) {
+                output.links = [];
+            }
+            output.links.push(link_info.id);
+            //connect in input
+            target_node.inputs[target_slot].link = link_info.id;
+            if (this.graph) {
+                this.graph._version++;
+            }
+            if (this.onConnectionsChange) {
+                this.onConnectionsChange(
+                    LiteGraph.OUTPUT,
+                    slot,
+                    true,
+                    link_info,
+                    output
+                );
+            } //link_info has been created now, so its updated
+            if (target_node.onConnectionsChange) {
+                target_node.onConnectionsChange(
+                    LiteGraph.INPUT,
+                    target_slot,
+                    true,
+                    link_info,
+                    input
+                );
+            }
+            if (this.graph && this.graph.onNodeConnectionChange) {
+                this.graph.onNodeConnectionChange(
+                    LiteGraph.INPUT,
+                    target_node,
+                    target_slot,
+                    this,
+                    slot
+                );
+                this.graph.onNodeConnectionChange(
+                    LiteGraph.OUTPUT,
+                    this,
+                    slot,
+                    target_node,
+                    target_slot
+                );
+            }
+        }
 
         this.setDirtyCanvas(false, true);
 		this.graph.afterChange();