feat: llm support struct output (#17994)

Co-authored-by: twwu <twwu@dify.ai>
Co-authored-by: zxhlyh <jasonapring2015@outlook.com>

web/app/components/workflow/hooks/use-workflow-variables.ts

@@ -8,6 +8,8 @@ import type {
   ValueSelector,
   Var,
 } from '@/app/components/workflow/types'
+import { useIsChatMode } from './use-workflow'
+import { useStoreApi } from 'reactflow'
 
 export const useWorkflowVariables = () => {
   const { t } = useTranslation()
@@ -75,3 +77,37 @@ export const useWorkflowVariables = () => {
     getCurrentVariableType,
   }
 }
+
+export const useWorkflowVariableType = () => {
+  const store = useStoreApi()
+  const {
+    getNodes,
+  } = store.getState()
+  const { getCurrentVariableType } = useWorkflowVariables()
+
+  const isChatMode = useIsChatMode()
+
+  const getVarType = ({
+    nodeId,
+    valueSelector,
+  }: {
+    nodeId: string,
+    valueSelector: ValueSelector,
+  }) => {
+    const node = getNodes().find(n => n.id === nodeId)
+    const isInIteration = !!node?.data.isInIteration
+    const iterationNode = isInIteration ? getNodes().find(n => n.id === node.parentId) : null
+    const availableNodes = [node]
+
+    const type = getCurrentVariableType({
+      parentNode: iterationNode,
+      valueSelector,
+      availableNodes,
+      isChatMode,
+      isConstant: false,
+    })
+    return type
+  }
+
+  return getVarType
+}