On one of my pages in my app I'm doing two api calls with graphql apollo client. One is document, the other one menu. I need menu data in one of my components so I want to use readQuery in order to not to fetch it again. What I'm doing is:
const client = useApolloClient();
try {
const testData = client.readQuery({
query: gql`
query ($result: String) {
menu(result: $result) {
text
}
}
`,
variables: {
result: „testresult”
},
});
console.log(testData);
} catch(e) {
console.log(e);
}
What graphQL is doing is looking for document root query so the error looks like this:
Invariant Violation: Can't find field menu({"lang":"en-us"}) on object
{
"document({\"lanf\":\"en-us\",\"id\":\"mySite\"})": {
"type": "id",
"generated": false,
"id": "XO5tyxAAALGzcYGG",
"typename": "Document"
}
}.
I believe that it is because menu data is not there yet.
How can I wait until it will be there?
You are right. You are getting an error because the data is not in cache yet:
The query method, on the other hand, may send a request to your server if the appropriate data is not in your cache whereas readQuery will throw an error if the data is not in your cache. readQuery will always read from the cache.
https://www.apollographql.com/docs/react/advanced/caching/#readquery
To do what you want use the a normal query with a cache-only fetchPolicy.
https://www.apollographql.com/docs/react/api/react-apollo/#optionsfetchpolicy
Related
I guess this is a simple issue, but I am stuck here for a while, so any advice may be helpful!
I have a react app and I am calling a GraphQL api (with apollo). Inside an arrow function component I have:
const [executeQuery, { data }] = useLazyQuery(GET_ALL_TASKS);
const findId = (step) => {
executeQuery({
variables: {
"query": {
"state": "CREATED",
"taskDefinitionId": "something"
}
}
})
}
The query is successful and in the browser inspect panel I get this as the graphql response:
{
"data" : {
"tasks" : [ {
"id" : "2251",
"name" : "some_name",
"__typename" : "Task"
} ]
}
}
In my code I want to use the retrieved id. How can I isolate the id from the response? When I am trying to access the data I get an undefined error.
Thank you!
Not sure why you are wrapping your executeQuery in a function.
The data will be part of the response so you can get it like this:
const {data, loading} = executeQuery({
variables: {
"query": {
"state": "CREATED",
"taskDefinitionId": "something"
}
}
})
// may also need to check for the error state
if(loading){
console.log("Loading...")
}else{
/// the ids seem to be an array of objects
const ids = data.tasks.map((task)=> task.id)
console.log(ids)
}
For anyone who may have the same problem, I realized it is a caching error happening in apollo client. I couldn't figure out the solution. However, I temporarily solved it by downgrading the apollo client dependency to version 3.2.5
I am using apollo v3 with a create-react app. I fire a query with useQuery and expect results to be cached, but they are not.
In my App.jsx, I have:
const client = new ApolloClient({
uri: `${api}/graphql`,
cache: new InMemoryCache()
})
I wrap my app with the ApolloProvider.
I have a provider that uses this graphql query to fetch a list of users:
const USERS_QUERY = gql`
query GetUsers {
users {
id
email
fullName
}
}
`
The query works, when I inspect the apollo tab in chrome devtools, I see nothing in the cache section.
My questions:
Why are the results not cached if I am using the useQuery from #apollo/client?
const { loading, error, data } = useQuery(USERS_QUERY)
I thought results should be cached automatically.
I also tried to add a type policy:
cache: new InMemoryCache({
typePolicies: {
Users: {
keyFields: ['id']
}
}
})
But I think I use this if I want to normalise with a different key the cache, or if I want to decide how to merge new data by myself. But first I need to have the data in my cache
As far as I know, this is because your query does not have any input arguments / variables, so the cache does not know what item to get from the cache when the query is called again. From what I understand, the cache is only used when a specific piece of data is looked for with an ID; otherwise, if it is a generic query, the data might have changed and so is not cached.
I am using GraphQL with Apollo-Client in my React(Typescript) application with an in memory cache. The cache is updated on new items being added which works fine with no errors.
When items are removed a string is returned from GraphQL Apollo-Server backend stating the successful delete operation which initiates the update function to be called which reads the cache and then modifies it by filtering out the id of the item. This is performed using the mutation hook from Apollo-Client.
const [deleteBook] = useMutation<{ deleteBook: string }, DeleteBookProps>(DELETE_BOOK_MUTATION, {
variables: { id },
onError(error) {
console.log(error);
},
update(proxy) {
const bookCache = proxy.readQuery<{ getBooks: IBook[] }>({ query: GET_BOOKS_QUERY });
if (bookCache) {
proxy.writeQuery<IGetBooks>({
query: GET_BOOKS_QUERY,
data: { getBooks: bookCache.getBooks.filter((b) => b._id !== id) },
});
}
},
});
The function works and the frontend is updated with the correct items in cache, however the following error is displayed in the console:
Cache data may be lost when replacing the getBooks field of a Query object.
To address this problem (which is not a bug in Apollo Client), define a custom merge function for the Query.getBooks field, so InMemoryCache can safely merge these objects:
existing: [{"__ref":"Book:5f21280332de1d304485ae80"},{"__ref":"Book:5f212a1332de1d304485ae81"},{"__ref":"Book:5f212a6732de1d304485ae82"},{"__ref":"Book:5f212a9232de1d304485ae83"},{"__ref":"Book:5f21364832de1d304485ae84"},{"__ref":"Book:5f214e1932de1d304485ae85"},{"__ref":"Book:5f21595a32de1d304485ae88"},{"__ref":"Book:5f2166601f6a633ae482bae4"}]
incoming: [{"__ref":"Book:5f212a1332de1d304485ae81"},{"__ref":"Book:5f212a6732de1d304485ae82"},{"__ref":"Book:5f212a9232de1d304485ae83"},{"__ref":"Book:5f21364832de1d304485ae84"},{"__ref":"Book:5f214e1932de1d304485ae85"},{"__ref":"Book:5f21595a32de1d304485ae88"},{"__ref":"Book:5f2166601f6a633ae482bae4"}]
For more information about these options, please refer to the documentation:
* Ensuring entity objects have IDs: https://go.apollo.dev/c/generating-unique-identifiers
* Defining custom merge functions: https://go.apollo.dev/c/merging-non-normalized-objects
Is there a better way to update the cache so this error won't be received?
I too faced the exact same warning, and unfortunately didn't come up with a solution other than the one suggested here: https://go.apollo.dev/c/merging-non-normalized-objects
const client = new ApolloClient({
....
cache: new InMemoryCache({
typePolicies: {
Query: {
fields: {
getBooks: {
merge(existing, incoming) {
return incoming;
},
},
},
},
}
}),
});
(I am not sure weather I wrote your fields and types correctly though, so you might change this code a bit)
Basically, the code above let's apollo client how to deal with mergeable data. In this case, I simply replace the old data with a new one.
I wonder though, if there's a better solution
I've also faced the same problem. I've come across a GitHub thread that offers two alternative solutions here.
The first is evicting what's in your cache before calling cache.writeQuery:
cache.evict({
// Often cache.evict will take an options.id property, but that's not necessary
// when evicting from the ROOT_QUERY object, as we're doing here.
fieldName: "notifications",
// No need to trigger a broadcast here, since writeQuery will take care of that.
broadcast: false,
});
In short this flushes your cache so your new data will be the new source of truth. There is no concern about losing your old data.
An alternative suggestion for the apollo-client v3 is posted further below in the same thread:
cache.modify({
fields: {
notifications(list, { readField }) {
return list.filter((n) => readField('id', n) !==id)
},
},
})
This way removes a lot of boilerplate so you don't need to use readQuery, evict, and writeQuery. The problem is that if you're running Typescript you'll run into some implementation issues. Under-the-hood the format used is InMemoryCache format instead of the usual GraphQL data. You'll be seeing Reference objects, types that aren't inferred, and other weird things.
I am trying to update my chache after succesfully executing a mutation. Here is my query and mutation:
export const Dojo_QUERY = gql`
query Dojo($id: Int!){
dojo(id: $id){
id,
name,
logoUrl,
location {
id,
city,
country
},
members{
id
},
disziplines{
id,
name
}
}
}`;
export const addDiszipline_MUTATION = gql`
mutation createDisziplin($input:DisziplineInput!,$dojoId:Int!){
createDisziplin(input:$input,dojoId:$dojoId){
disziplin{
name,
id
}
}
}`;
and my mutation call:
const [createDisziplin] = useMutation(Constants.addDiszipline_MUTATION,
{
update(cache, { data: { createDisziplin } }) {
console.log(cache)
const { disziplines } = cache.readQuery({ query: Constants.Dojo_QUERY,variables: {id}});
console.log(disziplines)
cache.writeQuery({
...some update logic (craches in line above)
});
}
}
);
when i execute this mutation i get the error
Invariant Violation: "Can't find field dojo({"id":1}) on object {
"dojo({\"id\":\"1\"})": {
"type": "id",
"generated": false,
"id": "DojoType:1",
"typename": "DojoType"
}
}."
In my client cache i can see
data{data{DojoType {...WITH ALL DATA INSIDE APPART FROM THE NEW DISZIPLINE}}
and
data{data{DisziplineType {THE NEW OBJECT}}
There seems to be a lot of confusion around the client cache around the web. Somehow none of the posed solutions helped, or made any sense to me. Any help would be greatly appreciated.
EDIT 1:
Maybe this can help?
ROOT_QUERY: {…}
"dojo({\"id\":\"1\"})": {…}
generated: false
id: "DojoType:1"
type: "id"
typename: "DojoType"
<prototype>: Object { … }
<prototype>: Object { … }
Edit 2
I have taken Herku advice and started using fragment. however it still seems to not quite work.
My udated code:
const [createDisziplin] = useMutation(Constants.addDiszipline_MUTATION,
{
update(cache, { data: { createDisziplin } }) {
console.log(cache)
const { dojo } = cache.readFragment(
{ fragment: Constants.Diszilines_FRAGMENT,
id:"DojoType:"+id.toString()});
console.log(dojo)
}
}
);
with
export const Diszilines_FRAGMENT=gql`
fragment currentDojo on Dojo{
id,
name,
disziplines{
id,
name
}
}
`;
however the result from console.log(dojo) is still undefined.Any advice?
So I think your actual error is that you have to supply the ID as as a string: variables: {id: id.toString()}. You can see that these two lines are different:
dojo({\"id\":1})
dojo({\"id\":\"1\"})
But I would highly suggest to use readFragment instead of readQuery and update the dojo with the ID supplied. This should update the query as well and all other occurrences of the dojo in all your queries. You can find documentation on readFragment here.
Another trick is as well to simply return the whole dojo in the response of the mutation. I would say people should be less afraid of that and not do to much cache updates because cache updates are implicit behaviour of your API that is nowhere in your type system. That the new disziplin can be found in the disziplins field is now encoded in your frontend. Imagine you want to add another step here where new disziplins have to be approved first before they end up in there. If the mutation returns the whole dojo a simple backend change would do the job and your clients don't have to be aware of that behaviour.
What I am trying to do
Render a page server side with data from our graphql server with errors.
Context
Our GraphQL server speaks to multiple APIs and returns a graphQL response which is handled by Apollo UI.
Certain GraphQL errors are not considered critical, and we want to still render a page with it. E.g.
data: {
thing: {
id: "1234"
name: "Thing"
nonCriticalData: null
},
error: {
graphQLErrors: [
path: ['thing', 'nonCriticalData']
]
}
}
With the above response we get from Apollo, we want to still render a page with thing. Looking at the implementation of getDataFromTree here, any error will get thrown, without the rest of the data.
How we plan to handle our errors
Here is a snippet of how we plan to handle our code:
getDataFromTree(app)
.then(() => {})
.catch(error => {
const content = ReactDOMServer.renderToString(app);
const { data } = client.getInitialState();
console.log("data", data); <-------------- We need data here
console.log("error", error); <———————— errors are here
// render page with data
});
Please let me know if there are ways around this, or whether I have missed
something.
Extra questions:
Should getDataFromTree even throw errors? It feels like the responsibility should lie with the consumer.