T
TanStack•3d ago
continuing-cyan

How to combine two TanStack Query results into a single object in Angular?

I have two separate queries using @tanstack/angular-query: 
roles = injectQuery(() => ({
  enabled: this.user.data(),
  queryKey: ['roles'],
  queryFn: () =>
    lastValueFrom(getRoles({ roles: this.user.data().roles })),
}));

user = injectQuery(() => ({
  queryKey: ['user'],
  queryFn: () => lastValueFrom(getUser()),
}));
roles = injectQuery(() => ({
  enabled: this.user.data(),
  queryKey: ['roles'],
  queryFn: () =>
    lastValueFrom(getRoles({ roles: this.user.data().roles })),
}));

user = injectQuery(() => ({
  queryKey: ['user'],
  queryFn: () => lastValueFrom(getUser()),
}));
I want to keep these queries separate, but in the UI I want to consume them as one combined object, e.g.: 
<div *ngIf="user.data() as user">
  roles: {{ user.roles.length }}
</div>
<div *ngIf="user.data() as user">
  roles: {{ user.roles.length }}
</div>
Ideally something like: 
userActive = injectQueries(() => ({
  queries: [this.user, this.roles],
  select: (user, roles) => this.toUser(user, roles),
}));

toUser(user, roles) {
  return { ...user, roles: roles };
}
userActive = injectQueries(() => ({
  queries: [this.user, this.roles],
  select: (user, roles) => this.toUser(user, roles),
}));

toUser(user, roles) {
  return { ...user, roles: roles };
}
But I can't figure out how to combine the results like this. I also tried a computed signal, but computed() returns null until both queries load, and I'd prefer to stay within the TanStack Query API: 
activeUser = computed(() => {
  const user = this.user.data();
  const roles = this.roles.data();
  if (!user) return;
  if (!roles) return;

  return this.toUser(user, roles);
});
activeUser = computed(() => {
  const user = this.user.data();
  const roles = this.roles.data();
  if (!user) return;
  if (!roles) return;

  return this.toUser(user, roles);
});
Is there a built-in way in TanStack Query for Angular to derive/merge the results of two queries into one object (similar to injectQueries + select), while still keeping both queries independent?
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