Extract tree expand/collapse logic as hook (#618)

src/hooks/treeHooks.ts

@@ -0,0 +1,73 @@
+import { ref } from 'vue'
+import type { TreeNode } from 'primevue/treenode'
+
+export function useTreeExpansion() {
+  const expandedKeys = ref<Record<string, boolean>>({})
+
+  const toggleNode = (node: TreeNode) => {
+    if (node.key && typeof node.key === 'string') {
+      if (node.key in expandedKeys.value) {
+        delete expandedKeys.value[node.key]
+      } else {
+        expandedKeys.value[node.key] = true
+      }
+    }
+  }
+
+  const toggleNodeRecursive = (node: TreeNode) => {
+    if (node.key && typeof node.key === 'string') {
+      if (node.key in expandedKeys.value) {
+        collapseNode(node)
+      } else {
+        expandNode(node)
+      }
+    }
+  }
+
+  const expandNode = (node: TreeNode) => {
+    if (
+      node.key &&
+      typeof node.key === 'string' &&
+      node.children &&
+      node.children.length
+    ) {
+      expandedKeys.value[node.key] = true
+
+      for (const child of node.children) {
+        expandNode(child)
+      }
+    }
+  }
+
+  const collapseNode = (node: TreeNode) => {
+    if (
+      node.key &&
+      typeof node.key === 'string' &&
+      node.children &&
+      node.children.length
+    ) {
+      delete expandedKeys.value[node.key]
+
+      for (const child of node.children) {
+        collapseNode(child)
+      }
+    }
+  }
+
+  const onNonLeafClick = (e: MouseEvent, node: TreeNode) => {
+    if (e.ctrlKey) {
+      toggleNodeRecursive(node)
+    } else {
+      toggleNode(node)
+    }
+  }
+
+  return {
+    expandedKeys,
+    toggleNode,
+    toggleNodeRecursive,
+    expandNode,
+    collapseNode,
+    onNonLeafClick
+  }
+}