Function getStartingNodes

packages/server/src/utils/index.ts:230–259

(graph: INodeDirectedGraph, endNodeId: string)

 * @param {string} endNodeId
 */
export const getStartingNodes = (graph: INodeDirectedGraph, endNodeId: string) => {
    const depthQueue: IDepthQueue = {
        [endNodeId]: 0
    }

    // Assuming that this is a directed acyclic graph, there will be no infinite loop problem.
    const walkGraph = (nodeId: string) => {
        const depth = depthQueue[nodeId]
        graph[nodeId].flatMap((id) => {
            depthQueue[id] = Math.max(depthQueue[id] ?? 0, depth + 1)
            walkGraph(id)
        })
    }

    walkGraph(endNodeId)

    const maxDepth = Math.max(...Object.values(depthQueue))
    const depthQueueReversed: IDepthQueue = {}
    for (const nodeId in depthQueue) {
        if (Object.prototype.hasOwnProperty.call(depthQueue, nodeId)) {
            depthQueueReversed[nodeId] = Math.abs(depthQueue[nodeId] - maxDepth)
        }
    }

    const startingNodeIds = Object.entries(depthQueueReversed)
        .filter(([_, depth]) => depth === 0)
        .map(([id, _]) => id)

    return { startingNodeIds, depthQueue: depthQueueReversed }
}

/**
 * Get all connected nodes from startnode