FetchtResult for mutation

[fetis]

Holla!

.mutate() method of apollo-angular uses FetchResult<T> for the return type, which internally uses ExecutionResult<T> from graphql module itself. The data property in ExecutionResult defined as optional and nullable. This brings problems because TS always complain that data might be null even when your mutation result is neve nullable (we use types generated from the schema). So you have to fight with nullability and of course, it's confusing because the schema result is non-nullable.

In contradiction query method defines data as data<T>, so we don't have this problem for queries.

What would be a solution to this?

[psyphore]

for some reason, the apollo-angular docs have been neglected, so this is how I read the data from a mutation result:

`
private apolloAuthenticated = new BehaviorSubject(null); // declare subject
public signIn(credentials: SignInCredentials) {
this.apollo
.mutate<SignInResponse, SignInCredentials>({
mutation: SIGN_IN_MUTATION,
variables: { creds: credentials.creds },
update: (proxy, { data }) => {
this.apolloAuthenticated.next(data); // update the subject here
}
}).subscribe();

return this.apolloAuthenticated.asObservable();

}

// consume the subject
return this.dataService.signIn(payload)
.pipe(
tap((data) => data ? dispatch(new SignInSuccess(data)) : null),
catchError((error) => of(dispatch(new SignInFailure(error.message))))
);
`

[fetis]

@psyphore thanks for a comment, but I'm not sure it solves my problem