upstream-tanstack-query/docs/framework/angular/reference/functions/injectMutationState.md

id, title

id	title
injectMutationState	injectMutationState

function injectMutationState<TResult>(injectMutationStateFn, options?): Signal<TResult[]>;

Defined in: packages/angular-query-experimental/src/inject-mutation-state.ts:106

Injects a signal that gives you access to all mutations in the MutationCache. You can pass filters (MutationFilters) to narrow down your mutations, and select to transform the mutation state.

Type Parameters

TResult

TResult = MutationState<unknown, Error, unknown, unknown>

Parameters

injectMutationStateFn

() => MutationStateOptions<TResult>

A function returning the filters to narrow down matched mutations, and an optional select to transform the mutation state. Similar to computed from Angular, this function runs in the reactive context, so signals read inside it re-narrow the matched mutations.

options?

InjectMutationStateOptions

Additional configuration

Returns

Signal<TResult[]>

A Signal with an Array of whatever select returns for each matching mutation.

Examples

Get all variables of all running mutations:

@Component({
  selector: 'pending-posts',
  template: `{{ pendingVariables().length }} posts saving...`,
})
export class PendingPosts {
  readonly pendingVariables = injectMutationState(() => ({
    filters: { status: 'pending' },
    select: (mutation) => mutation.state.variables,
  }))
}

Get all data for specific mutations via the mutationKey:

const mutationKey = ['posts']

@Component({
  selector: 'posts',
  template: `
    <button (click)="createPost()">
      Create post ({{ savedPosts().length }} saved so far)
    </button>
  `,
})
export class Posts {
  // Some mutation that we want to get the state for
  readonly createPostMutation = injectMutation(() => ({
    mutationKey,
    mutationFn: createPosts,
  }))

  readonly savedPosts = injectMutationState(() => ({
    // this mutation key needs to match the mutation key of the given mutation (see above)
    filters: { mutationKey, status: 'success' },
    select: (mutation) => mutation.state.data,
  }))

  createPost() {
    this.createPostMutation.mutate(['New Post'])
  }
}