Mutations & Queries

TanStack Query Setup

PinTeach uses TanStack Query 5 for all server state management. The API client is a thin fetch wrapper in apps/app/src/lib/api.ts.

API Client

export const api = {
  get: <T>(path: string) => apiRequest<T>(path),
  post: <T>(path: string, body: unknown) =>
    apiRequest<T>(path, { method: 'POST', body: JSON.stringify(body) }),
  patch: <T>(path: string, body: unknown) =>
    apiRequest<T>(path, { method: 'PATCH', body: JSON.stringify(body) }),
  put: <T>(path: string, body: unknown) =>
    apiRequest<T>(path, { method: 'PUT', body: JSON.stringify(body) }),
  delete: <T>(path: string) =>
    apiRequest<T>(path, { method: 'DELETE' }),
};

Query Pattern

const { data, isLoading } = useQuery({
  queryKey: ['teacher-sessions', teacherId],
  queryFn: () => api.get<Session[]>('/teacher/sessions'),
});

Common Query Keys

Key Pattern	Data
`['teacher-sessions']`	Session list
`['teacher-calendar', start, end]`	Calendar events
`['teacher-students']`	Student list
`['teacher-services']`	Service list
`['teacher-reviews']`	Review list
`['teacher-dashboard']`	Dashboard KPIs
`['teacher-payments']`	Payment history

Mutation Pattern

const mutation = useMutation({
  mutationFn: (input: CreateInput) =>
    api.post('/teacher/sessions', input),
  onSuccess: () => {
    queryClient.invalidateQueries({ queryKey: ['teacher-sessions'] });
    toast.success(t('sessions.created'));
  },
  onError: () => toast.error(t('common.error')),
});

Optimistic Mutations

For frequent, low-risk actions, use useOptimisticMutation from hooks/mutations/:

import { useOptimisticMutation } from '@/hooks/mutations';

const mutation = useOptimisticMutation({
  mutationFn: (id: string) =>
    api.post(`/teacher/sessions/${id}/complete`),
  queryKeys: [['teacher-sessions'], ['teacher-calendar']],
  onOptimisticUpdate: ({ queryClient, snapshot }) => {
    // Update cache immediately
  },
});

How It Works

Cancel in-flight queries
Create snapshot (createSnapshot)
Apply optimistic cache update
On error: rollback via restoreSnapshot
On settle: invalidate all queryKeys

Available Optimistic Hooks (11)

Complete session
Mark no-show
Toggle favorite
Move items (materials)
Reorder tags
Reorder categories
Submit mood
Read notification
Update review status
Bulk delete materials
Bulk tag materials

Calendar Update Helper

updateCalendarEvent prefix-matches ['teacher-calendar', ...] across date ranges for optimistic calendar updates.

Helpers

Helper	Purpose
`createSnapshot(queryClient, queryKeys)`	Save current cache state
`restoreSnapshot(queryClient, snapshot)`	Rollback to saved state
`updateCalendarEvent(queryClient, ...)`	Update calendar cache entries