本页内容
来自变更响应的更新
当处理那些在服务器上更新对象的 mutation 时，通常新的对象会在 mutation 的响应中自动返回。与其重新获取该项的任何查询并浪费一次我们已拥有数据的网络调用，不如利用 mutation 函数返回的对象，通过 Query Client 的 setQueryData 方法立即使用新数据更新现有查询。
tsx
const queryClient = useQueryClient()
const mutation = useMutation({
mutationFn: editTodo,
onSuccess: (data) => {
queryClient.setQueryData(['todo', { id: 5 }], data)
},
})
mutation.mutate({
id: 5,
name: 'Do the laundry',
})
// The query below will be updated with the response from the
// successful mutation
const { status, data, error } = useQuery({
queryKey: ['todo', { id: 5 }],
queryFn: fetchTodoById,
})
const queryClient = useQueryClient()
const mutation = useMutation({
mutationFn: editTodo,
onSuccess: (data) => {
queryClient.setQueryData(['todo', { id: 5 }], data)
},
})
mutation.mutate({
id: 5,
name: 'Do the laundry',
})
// The query below will be updated with the response from the
// successful mutation
const { status, data, error } = useQuery({
queryKey: ['todo', { id: 5 }],
queryFn: fetchTodoById,
})
你可能希望将 onSuccess 逻辑绑定到一个可重用的变更中，为此你可以像这样创建一个自定义钩子
tsx
const useMutateTodo = () => {
const queryClient = useQueryClient()
return useMutation({
mutationFn: editTodo,
// Notice the second argument is the variables object that the `mutate` function receives
onSuccess: (data, variables) => {
queryClient.setQueryData(['todo', { id: variables.id }], data)
},
})
}
const useMutateTodo = () => {
const queryClient = useQueryClient()
return useMutation({
mutationFn: editTodo,
// Notice the second argument is the variables object that the `mutate` function receives
onSuccess: (data, variables) => {
queryClient.setQueryData(['todo', { id: variables.id }], data)
},
})
}
不变性
通过 setQueryData 进行的更新必须以不可变的方式执行。请勿尝试通过原地修改（您从缓存中检索到的）数据来直接写入缓存。这可能一开始会奏效，但可能导致后续出现微妙的错误。
tsx
queryClient.setQueryData(['posts', { id }], (oldData) => {
if (oldData) {
// ❌ do not try this
oldData.title = 'my new post title'
}
return oldData
})
queryClient.setQueryData(
['posts', { id }],
// ✅ this is the way
(oldData) =>
oldData
? {
...oldData,
title: 'my new post title',
}
: oldData,
)
queryClient.setQueryData(['posts', { id }], (oldData) => {
if (oldData) {
// ❌ do not try this
oldData.title = 'my new post title'
}
return oldData
})
queryClient.setQueryData(
['posts', { id }],
// ✅ this is the way
(oldData) =>
oldData
? {
...oldData,
title: 'my new post title',
}
: oldData,
)
