migrating hooks, fixed colorMode

packages/svelte/src/lib/hooks/useHandleConnections.svelte.ts

@@ -0,0 +1,52 @@
+import { areConnectionMapsEqual, type HandleConnection, type HandleType } from '@xyflow/system';
+
+import { useStore } from '$lib/store';
+import { getContext } from 'svelte';
+
+export type useHandleConnectionsParams = {
+  type: HandleType;
+  nodeId?: string;
+  id?: string | null;
+};
+
+const initialConnections: HandleConnection[] = [];
+
+/**
+ *  Hook to check if a <Handle /> is connected to another <Handle /> and get the connections.
+ *
+ * @public
+ * @param param.nodeId
+ * @param param.type - handle type 'source' or 'target'
+ * @param param.id - the handle id (this is only needed if the node has multiple handles of the same type)
+ * @returns an array with connections
+ */
+export function useHandleConnections({
+  type,
+  nodeId: _nodeId,
+  id = null
+}: useHandleConnectionsParams) {
+  const { edges, connectionLookup } = $derived(useStore());
+
+  const contextNodeId = getContext<string>('svelteflow__node_id');
+  const nodeId = _nodeId ?? contextNodeId;
+
+  let prevConnections: Map<string, HandleConnection> | undefined = new Map();
+  let connectionsArray: HandleConnection[] = initialConnections;
+
+  const connections = $derived.by(() => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-expressions
+    edges;
+    const nextConnections = connectionLookup.get(`${nodeId}-${type}-${id || null}`);
+    if (!areConnectionMapsEqual(nextConnections, prevConnections)) {
+      prevConnections = nextConnections;
+      connectionsArray = Array.from(nextConnections?.values() || initialConnections);
+    }
+    return connectionsArray;
+  });
+
+  return {
+    get current() {
+      return connections;
+    }
+  };
+}