dify/web/app/components/workflow/nodes/loop/node.tsx

import type { FC } from 'react'
import type { LoopNodeType } from './types'
import type { NodeProps } from '@/app/components/workflow/types'
import { cn } from '@langgenius/dify-ui/cn'
import {
  Background,
  useNodesInitialized,
  useViewport,
} from '@xyflow/react'
import {
  memo,
  useEffect,
  useMemo,
} from 'react'
import { useWorkflowFlowNodes } from '../../hooks/use-workflow-reactflow'
import {
  getNodeHeight,
  getNodeWidth,
} from '../../utils/node'
import { LoopStartNodeDumb } from '../loop-start'
import AddBlock from './add-block'
import { useNodeLoopInteractions } from './use-interactions'

const Node: FC<NodeProps<LoopNodeType>> = ({
  id,
  data,
}) => {
  const { zoom } = useViewport()
  const nodesInitialized = useNodesInitialized()
  const nodes = useWorkflowFlowNodes()
  const { handleNodeLoopRerender } = useNodeLoopInteractions()
  const childrenLayoutKey = useMemo(() => {
    return nodes
      .filter(node => node.parentId === id)
      .map(node => [
        node.id,
        node.position.x,
        node.position.y,
        getNodeWidth(node),
        getNodeHeight(node),
      ].join(':'))
      .join('|')
  }, [nodes, id])

  useEffect(() => {
    if (nodesInitialized)
      handleNodeLoopRerender(id)
  }, [nodesInitialized, childrenLayoutKey, id, handleNodeLoopRerender])

  return (
    <div className={cn(
      'relative h-full min-h-[90px] w-full min-w-[240px] rounded-2xl bg-workflow-canvas-workflow-bg',
    )}
    >
      <Background
        id={`loop-background-${id}`}
        className="z-0! rounded-2xl"
        gap={[14 / zoom, 14 / zoom]}
        size={2 / zoom}
        color="var(--color-workflow-canvas-workflow-dot-color)"
      />
      {
        data._isCandidate && (
          <LoopStartNodeDumb />
        )
      }
      {
        data._children?.length === 1 && (
          <AddBlock
            loopNodeId={id}
            loopNodeData={data}
          />
        )
      }

    </div>
  )
}

export default memo(Node)