diff --git a/src/litegraph.d.ts b/src/litegraph.d.ts
index ec4cbaf95..b35ce01c7 100644
--- a/src/litegraph.d.ts
+++ b/src/litegraph.d.ts
@@ -938,6 +938,17 @@ export declare class LGraphNode {
         _this: this,
         slotIndex: number
     ): boolean;
+
+    /**
+     * Called just before connection (or disconnect - if input is linked).
+     * A convenient place to switch to another input, or create new one.
+     * This allow for ability to automatically add slots if needed
+     * @param inputIndex
+     * @return selected input slot index, can differ from parameter value
+     */
+    onBeforeConnectInput?(
+        inputIndex: number
+    ): number;
     
     /** a connection changed (new one or removed) (LiteGraph.INPUT or LiteGraph.OUTPUT, slot, true if connected, link_info, input_info or output_info ) */
     onConnectionsChange(
diff --git a/src/litegraph.js b/src/litegraph.js
index 0c0c1347a..bd4d74512 100755
--- a/src/litegraph.js
+++ b/src/litegraph.js
@@ -3592,28 +3592,33 @@
             return null;
         }
 
-        //if there is something already plugged there, disconnect
-        if (target_node.inputs[target_slot].link != null) {
-            target_node.disconnectInput(target_slot);
-        }
-
-        //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 link_info = 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 there is something already plugged there, disconnect
+            if (target_node.inputs[target_slot].link != null) {
+                target_node.disconnectInput(target_slot);
+            }
+
+            //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 link_info = null;
+
             link_info = new LLink(
                 ++this.graph.last_link_id,
                 input.type,