Files
xyflow/packages/react/src/hooks/useNodeConnections.ts
T

88 lines
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TypeScript

import { useEffect, useMemo, useRef } from 'react';
import {
Connection,
NodeConnection,
HandleType,
areConnectionMapsEqual,
handleConnectionChange,
errorMessages,
} from '@xyflow/system';
import { useStore } from './useStore';
import { useNodeId } from '../contexts/NodeIdContext';
const error014 = errorMessages['error014']();
type UseNodeConnectionsParams = {
id?: string;
handleType?: HandleType;
handleId?: string;
onConnect?: (connections: Connection[]) => void;
onDisconnect?: (connections: Connection[]) => void;
};
/**
* This hook returns an array of connections on a specific node, handle type ('source', 'target') or handle ID.
*
* @public
* @param param.id - node id - optional if called inside a custom node
* @param param.handleType - filter by handle type 'source' or 'target'
* @param param.handleId - filter by handle id (this is only needed if the node has multiple handles of the same type)
* @param param.onConnect - gets called when a connection is established
* @param param.onDisconnect - gets called when a connection is removed
* @returns an array with connections
*
* @example
* ```jsx
*import { useNodeConnections } from '@xyflow/react';
*
*export default function () {
* const connections = useNodeConnections({
* handleType: 'target',
* handleId: 'my-handle',
* });
*
* return (
* <div>There are currently {connections.length} incoming connections!</div>
* );
*}
*```
*/
export function useNodeConnections({
id,
handleType,
handleId,
onConnect,
onDisconnect,
}: UseNodeConnectionsParams = {}): NodeConnection[] {
const nodeId = useNodeId();
const currentNodeId = id ?? nodeId;
if (!currentNodeId) {
throw new Error(error014);
}
const prevConnections = useRef<Map<string, NodeConnection> | null>(null);
const connections = useStore(
(state) =>
state.connectionLookup.get(
`${currentNodeId}${handleType ? (handleId ? `-${handleType}-${handleId}` : `-${handleType}`) : ''}`
),
areConnectionMapsEqual
);
useEffect(() => {
// @todo dicuss if onConnect/onDisconnect should be called when the component mounts/unmounts
if (prevConnections.current && prevConnections.current !== connections) {
const _connections = connections ?? new Map();
handleConnectionChange(prevConnections.current, _connections, onDisconnect);
handleConnectionChange(_connections, prevConnections.current, onConnect);
}
prevConnections.current = connections ?? new Map();
}, [connections, onConnect, onDisconnect]);
return useMemo(() => Array.from(connections?.values() ?? []), [connections]);
}