Files
xyflow/packages/svelte/src/lib/hooks/useHandleConnections.ts
T

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TypeScript

import { derived } from 'svelte/store';
import { areConnectionMapsEqual, type HandleConnection, type HandleType } from '@xyflow/system';
import { useStore } from '$lib/store';
import { getContext } from 'svelte';
export type useHandleConnectionsParams = {
type: HandleType;
nodeId?: string;
id?: string | null;
};
const initialConnections: HandleConnection[] = [];
/**
* Hook to check if a <Handle /> is connected to another <Handle /> and get the connections.
*
* @public
* @param param.nodeId
* @param param.type - handle type 'source' or 'target'
* @param param.id - the handle id (this is only needed if the node has multiple handles of the same type)
* @returns an array with connections
*/
export function useHandleConnections({ type, nodeId, id = null }: useHandleConnectionsParams) {
const { edges, connectionLookup } = useStore();
const _nodeId = getContext<string>('svelteflow__node_id');
const currentNodeId = nodeId ?? _nodeId;
let prevConnections: Map<string, HandleConnection> | undefined = undefined;
return derived(
[edges, connectionLookup],
([, connectionLookup], set) => {
const nextConnections = connectionLookup.get(`${currentNodeId}-${type}-${id || null}`);
if (!areConnectionMapsEqual(nextConnections, prevConnections)) {
prevConnections = nextConnections;
set(Array.from(prevConnections?.values() || []));
}
},
initialConnections
);
}