| --- |
| id: optimistic-updates |
| title: Optimistic Updates |
| ref: docs/framework/react/guides/optimistic-updates.md |
| replace: |
| { |
| 'React': 'Angular', |
| 'useMutation': 'injectMutation', |
| 'hook': 'function', |
| 'useMutationState': 'injectMutationState', |
| 'addTodoMutation': 'addTodo', |
| } |
| --- |
| |
| [//]: # 'ExampleUI1' |
|
|
| ```ts |
| addTodo = injectMutation(() => ({ |
| mutationFn: (newTodo: string) => axios.post('/api/data', { text: newTodo }), |
| // make sure to _return_ the Promise from the query invalidation |
| // so that the mutation stays in `pending` state until the refetch is finished |
| onSettled: async () => { |
| return await queryClient.invalidateQueries({ queryKey: ['todos'] }) |
| }, |
| })) |
| ``` |
|
|
| [//]: # 'ExampleUI1' |
| [//]: # 'ExampleUI2' |
|
|
| ```angular-ts |
| @Component({ |
| template: ` |
| @for (todo of todos.data(); track todo.id) { |
| <li>{{ todo.title }}</li> |
| } |
| @if (addTodo.isPending()) { |
| <li style="opacity: 0.5">{{ addTodo.variables() }}</li> |
| } |
| `, |
| }) |
| class TodosComponent {} |
| ``` |
|
|
| [//]: # 'ExampleUI2' |
| [//]: # 'ExampleUI3' |
|
|
| ```angular-ts |
| @Component({ |
| template: ` |
| @if (addTodo.isError()) { |
| <li style="color: red"> |
| {{ addTodo.variables() }} |
| <button (click)="addTodo.mutate(addTodo.variables())">Retry</button> |
| </li> |
| } |
| `, |
| }) |
| class TodosComponent {} |
| ``` |
|
|
| [//]: # 'ExampleUI3' |
| [//]: # 'ExampleUI4' |
|
|
| ```ts |
| // somewhere in your app |
| addTodo = injectMutation(() => ({ |
| mutationFn: (newTodo: string) => axios.post('/api/data', { text: newTodo }), |
| onSettled: () => queryClient.invalidateQueries({ queryKey: ['todos'] }), |
| mutationKey: ['addTodo'], |
| })) |
| |
| // access variables somewhere else |
| |
| mutationState = injectMutationState<string>(() => ({ |
| filters: { mutationKey: ['addTodo'], status: 'pending' }, |
| select: (mutation) => mutation.state.variables, |
| })) |
| ``` |
|
|
| [//]: # 'ExampleUI4' |
| [//]: # 'Example' |
|
|
| ```ts |
| queryClient = inject(QueryClient) |
| |
| updateTodo = injectMutation(() => ({ |
| mutationFn: updateTodo, |
| // When mutate is called: |
| onMutate: async (newTodo) => { |
| // Cancel any outgoing refetches |
| // (so they don't overwrite our optimistic update) |
| await this.queryClient.cancelQueries({ queryKey: ['todos'] }) |
| |
| // Snapshot the previous value |
| const previousTodos = client.getQueryData(['todos']) |
| |
| // Optimistically update to the new value |
| this.queryClient.setQueryData(['todos'], (old) => [...old, newTodo]) |
| |
| // Return a context object with the snapshotted value |
| return { previousTodos } |
| }, |
| // If the mutation fails, |
| // use the context returned from onMutate to roll back |
| onError: (err, newTodo, context) => { |
| client.setQueryData(['todos'], context.previousTodos) |
| }, |
| // Always refetch after error or success: |
| onSettled: () => { |
| this.queryClient.invalidateQueries({ queryKey: ['todos'] }) |
| }, |
| })) |
| ``` |
|
|
| [//]: # 'Example' |
| [//]: # 'Example2' |
|
|
| ```ts |
| queryClient = inject(QueryClient) |
| |
| updateTodo = injectMutation(() => ({ |
| mutationFn: updateTodo, |
| // When mutate is called: |
| onMutate: async (newTodo) => { |
| // Cancel any outgoing refetches |
| // (so they don't overwrite our optimistic update) |
| await this.queryClient.cancelQueries({ queryKey: ['todos', newTodo.id] }) |
| |
| // Snapshot the previous value |
| const previousTodo = this.queryClient.getQueryData(['todos', newTodo.id]) |
| |
| // Optimistically update to the new value |
| this.queryClient.setQueryData(['todos', newTodo.id], newTodo) |
| |
| // Return a context with the previous and new todo |
| return { previousTodo, newTodo } |
| }, |
| // If the mutation fails, use the context we returned above |
| onError: (err, newTodo, context) => { |
| this.queryClient.setQueryData( |
| ['todos', context.newTodo.id], |
| context.previousTodo, |
| ) |
| }, |
| // Always refetch after error or success: |
| onSettled: (newTodo) => { |
| this.queryClient.invalidateQueries({ queryKey: ['todos', newTodo.id] }) |
| }, |
| })) |
| ``` |
|
|
| [//]: # 'Example2' |
| [//]: # 'Example3' |
|
|
| ```ts |
| injectMutation({ |
| mutationFn: updateTodo, |
| // ... |
| onSettled: (newTodo, error, variables, context) => { |
| if (error) { |
| // do something |
| } |
| }, |
| }) |
| ``` |
|
|
| [//]: # 'Example3' |
|
|
