reactjs - useQueries 的启用选项

Question

我正在尝试像这样使用 useQueries

function App({ users }) {
   const userQueries = useQueries(
     users.map(user => {
       return {
         queryKey: ['user', user.id],
         queryFn: () => fetchUserById(user.id),
       }
     })
   )
 }

然而，users 变量是由 useQuery 提供的，并且最初返回 undefined。这导致错误无法读取未定义的映射。我想像 useQuery 一样添加 enabled，但我在文档中的任何地方都没有看到它。你可以用一个简单的 useQuery 来做到这一点:

// Get the user
 const { data: user } = useQuery(['user', email], getUserByEmail)
 
 const userId = user?.id
 
 // Then get the user's projects
 const { isIdle, data: projects } = useQuery(
   ['projects', userId],
   getProjectsByUser,
   {
     // The query will not execute until the userId exists
     enabled: !!userId,
   }
 )
 
 // isIdle will be `true` until `enabled` is true and the query begins to fetch.
 // It will then go to the `isLoading` stage and hopefully the `isSuccess` stage :)

基本上我想要

function App({ users }) {
   const userQueries = useQueries(
     users.map(user => {
       return {
         queryKey: ['user', user.id],
         queryFn: () => fetchUserById(user.id),
         enabled: !!users
       }
     })
   )
 }

Answer 1

如果没有用户，您可以回退到传递给 useQueries 的空数组:

function App({ users }) {
   const userQueries = useQueries(
     users?.map(user => {
       return {
         queryKey: ['user', user.id],
         queryFn: () => fetchUserById(user.id),
       }
     }) ?? []
   )
 }