Refactor

app/src/components/Tree/TreeNode/effects/useAnimationToIndicateTopicUpdate.tsx

@@ -0,0 +1,22 @@
+import React, { useEffect } from 'react'
+
+export function useAnimationToIndicateTopicUpdate(
+  lastUpdate: number,
+  selected: boolean,
+  setShowUpdateAnimation: React.Dispatch<React.SetStateAction<boolean>>,
+  showUpdateAnimation: boolean
+) {
+  useEffect(() => {
+    if (Date.now() - lastUpdate < 3000 && !selected) {
+      setShowUpdateAnimation(true)
+    }
+  }, [lastUpdate, selected])
+  useEffect(() => {
+    if (showUpdateAnimation) {
+      const timeout = setTimeout(() => setShowUpdateAnimation(false), 500)
+      return function cleanup() {
+        clearTimeout(timeout)
+      }
+    }
+  }, [showUpdateAnimation])
+}

app/src/components/Tree/TreeNode/effects/useDeleteKeyCallback.tsx

@@ -0,0 +1,17 @@
+import * as q from '../../../../../../backend/src/Model'
+import React, { useCallback } from 'react'
+import { KeyCodes } from '../../../../utils/KeyCodes'
+import { treeActions } from '../../../../actions'
+
+export function useDeleteKeyCallback(topic: q.TreeNode<any>, actions: typeof treeActions) {
+  return useCallback(
+    (event: React.KeyboardEvent) => {
+      if (event.keyCode === KeyCodes.delete || event.keyCode === KeyCodes.backspace) {
+        event.stopPropagation()
+        event.preventDefault()
+        actions.clearTopic(topic, true, 50)
+      }
+    },
+    [topic]
+  )
+}

app/src/components/Tree/TreeNode/effects/useIsAllowedToAutoExpandState.tsx

@@ -0,0 +1,14 @@
+import { Props } from '..'
+import { useEffect, useState } from 'react'
+
+export function useIsAllowedToAutoExpandState(props: Props): boolean {
+  const { settings, treeNode, isRoot } = props
+  const [isAllowedToAutoExpand, setAllowAutoExpand] = useState(false)
+  useEffect(() => {
+    const newIsAllowedToAutoExpand = isRoot || treeNode.edgeCount() <= settings.get('autoExpandLimit')
+    if (newIsAllowedToAutoExpand !== isAllowedToAutoExpand) {
+      setAllowAutoExpand(newIsAllowedToAutoExpand)
+    }
+  }, [treeNode.edgeCount(), settings.get('autoExpandLimit')])
+  return isAllowedToAutoExpand
+}

app/src/components/Tree/TreeNode/effects/useViewModelSubscriptions.tsx

@@ -0,0 +1,44 @@
+import * as q from '../../../../../../backend/src/Model'
+import React, { useEffect } from 'react'
+import { TopicViewModel } from '../../../../model/TopicViewModel'
+
+export function useViewModelSubscriptions(
+  treeNode: q.TreeNode<TopicViewModel>,
+  nodeRef: React.MutableRefObject<HTMLDivElement | undefined>,
+  setSelected: (value: boolean) => void,
+  setCollapsedOverride: (value: boolean) => void
+) {
+  const selectionDidChange = () => {
+    const selected = treeNode.viewModel && treeNode.viewModel.isSelected()
+    treeNode.viewModel && setSelected(Boolean(selected))
+
+    if (selected && nodeRef && nodeRef.current) {
+      nodeRef.current.focus({ preventScroll: false })
+    }
+  }
+
+  const expandedDidChange = () => {
+    treeNode.viewModel && setCollapsedOverride(!treeNode.viewModel.isExpanded())
+  }
+
+  useEffect(() => {
+    addSubscriber()
+    return function cleanup() {
+      removeSubscriber()
+    }
+  }, [treeNode])
+
+  function addSubscriber() {
+    treeNode.viewModel = new TopicViewModel()
+    treeNode.viewModel.selectionChange.subscribe(selectionDidChange)
+    treeNode.viewModel.expandedChange.subscribe(expandedDidChange)
+  }
+
+  function removeSubscriber() {
+    if (treeNode.viewModel) {
+      treeNode.viewModel.selectionChange.unsubscribe(selectionDidChange)
+      treeNode.viewModel.expandedChange.unsubscribe(expandedDidChange)
+      treeNode.viewModel = undefined
+    }
+  }
+}