injectMutation

function injectMutation<TData, TError, TVariables, TOnMutateResult>(injectMutationFn: () => CreateMutationOptions<TData, TError, TVariables, TOnMutateResult>, options?: InjectMutationOptions): CreateMutationResult<TData, TError, TVariables, TOnMutateResult>;

Defined in: packages/angular-query-experimental/src/inject-mutation.ts:172

Unlike queries, mutations are typically used to create/update/delete data or perform server side-effects. injectMutation is the function for that. Unlike queries, mutations are not run automatically.

Type Parameters

TData

TData = unknown

TError

TError = Error

TVariables

TVariables = void

TOnMutateResult

TOnMutateResult = unknown

Parameters

injectMutationFn

() => CreateMutationOptions<TData, TError, TVariables, TOnMutateResult>

A function that returns mutation options. Similar to computed from Angular, this function runs in the reactive context, so signals read inside it drive the mutation's options.

injectMutationFn properties

Property	Type	Default value	Description
gcTime?	number	undefined	The time in milliseconds that an unused/inactive mutation remains in memory before it is garbage collected. Defaults to 5 * 60 * 1000 (5 minutes), or Infinity during SSR.
meta?	Record<string, unknown>	undefined	Additional payload to be stored on the mutation cache entry. Use it to pass information that can be read wherever the mutation is available, such as the onError and onSuccess callbacks of the MutationCache.
mutationFn?	(variables: TVariables, context: MutationFunctionContext) => Promise<TData>	undefined	The function that performs the asynchronous task this mutation runs. Required, unless a default mutation function has been set for the matching mutationKey via queryClient.setMutationDefaults. Receives the variables passed to mutate, and a MutationFunctionContext holding the QueryClient, the mutationKey and meta. Must return a promise that resolves the mutation's data.
mutationKey?	readonly unknown[]	undefined	The key to use for this mutation. Optional, but required to inherit defaults registered with queryClient.setMutationDefaults, and to match this mutation with useMutationState or queryClient.isMutating.
networkMode?	"online" \| "always" \| "offlineFirst"	'online'	Controls whether a mutation is allowed to run based on the current network connectivity. See Network Mode for more information.
onError?	(error: TError, variables: TVariables, onMutateResult: TOnMutateResult \| undefined, context: MutationFunctionContext) => unknown	undefined	This function fires when the mutation encounters an error, and is passed the error. If a promise is returned, it is awaited before onSettled runs.
onMutate?	(variables: TVariables, context: MutationFunctionContext) => TOnMutateResult \| Promise<TOnMutateResult>	undefined	This function fires before the mutation function runs, and receives the same variables. Useful for optimistic updates applied in the hope that the mutation succeeds. The value it returns is passed to onSuccess, onError and onSettled as onMutateResult, which is where an optimistic update is usually rolled back. If a promise is returned, it is awaited before the mutation function runs.
onSettled?	(data: TData \| undefined, error: TError \| null, variables: TVariables, onMutateResult: TOnMutateResult \| undefined, context: MutationFunctionContext) => unknown	undefined	This function fires when the mutation either succeeds or errors, and is passed either the data or the error. If a promise is returned, it is awaited before the mutation settles.
onSuccess?	(data: TData, variables: TVariables, onMutateResult: TOnMutateResult, context: MutationFunctionContext) => unknown	undefined	This function fires when the mutation succeeds, and is passed the mutation's result. If a promise is returned, it is awaited before onSettled runs.
retry?	\| number \| false \| true \| ((failureCount: number, error: TError) => boolean)	0	If false, failed mutations will not retry by default. If true, failed mutations will retry infinitely. If set to an integer number, e.g. 3, failed mutations will retry until the failed mutation count meets that number. If set to a function (failureCount, error) => boolean failed mutations will retry until the function returns false.
retryDelay?	number \| ((failureCount: number, error: TError) => number)	undefined	This function receives a retryAttempt integer and the actual Error and returns the delay to apply before the next attempt in milliseconds. Defaults to a function that applies exponential backoff, capped at 30 seconds.
scope?	MutationScope	undefined	Controls whether this mutation runs alongside others or waits its turn. Mutations sharing the same scope.id run serially, in the order they were started. Without a scope, a mutation runs as soon as it is triggered.
throwOnError?	boolean \| ((error: TError) => boolean)	false	Whether errors should be thrown instead of setting the error property. If set to true, all errors will be thrown to the nearest error boundary. If set to a function, it will be passed the error and should return a boolean indicating whether to throw the error (true) or return it as state (false).

options?

InjectMutationOptions

Additional configuration

options properties

Property	Type	Description
injector?	Injector	The Injector in which to create the mutation. If this is not provided, the current injection context will be used instead (via inject).

Returns

CreateMutationResult<TData, TError, TVariables, TOnMutateResult>

The mutation result. Value fields are exposed as a Signal — read data/error by calling them (e.g. mutation.data()) — while function fields (mutate, mutateAsync, reset) are called directly, unchanged. isSuccess/isError/isPending/isIdle are type-guard methods you can call to narrow whether data is defined.

Remarks

mutate/mutateAsync also accept per-call onSuccess/onError/onSettled callbacks as a second argument, useful for triggering call-site side effects (e.g. navigation) without coupling them to the shared mutation definition. Callbacks defined in injectMutationFn fire for every mutation; per-call callbacks fire only for the latest call you've made — mutateAsync gives you a promise per call instead, so you can await Promise.all/Promise.allSettled over several calls and see each one's outcome.

See

mutationOptions to share these options across multiple injectMutation call sites, or to look the mutation up elsewhere via its mutationKey (e.g. with injectMutationState).

Examples

@Component({
  selector: 'todos',
  template: `
    @if (addMutation.isPending()) {
      <span>Adding todo...</span>
    } @else if (addMutation.isError()) {
      <div>An error occurred: {{ addMutation.error()?.message }}</div>
    }
    <button (click)="addMutation.mutate('Item')">Add</button>
  `,
})
export class Todos {
  readonly #queryClient = inject(QueryClient)

  readonly addMutation = injectMutation(() => ({
    mutationFn: addTodo,
    onSuccess: () => this.#queryClient.invalidateQueries({ queryKey: ['todos'] }),
  }))
}

Optimistic update via onMutate, rolling back on onError:

@Component({
  selector: 'todos',
  template: `<button (click)="addMutation.mutate('Item')">Add</button>`,
})
export class Todos {
  readonly #queryClient = inject(QueryClient)

  readonly addMutation = injectMutation(() => ({
    mutationFn: addTodo,
    onMutate: async (newTodo) => {
      await this.#queryClient.cancelQueries({ queryKey: ['todos'] })
      const previousTodos = this.#queryClient.getQueryData<Array<string>>(['todos'])

      this.#queryClient.setQueryData<Array<string>>(['todos'], (old) => [
        ...(old ?? []),
        newTodo,
      ])

      // Passed to `onError` as `onMutateResult` if the mutation fails.
      return { previousTodos }
    },
    onError: (_err, _newTodo, onMutateResult) => {
      this.#queryClient.setQueryData(['todos'], onMutateResult?.previousTodos)
    },
    onSettled: () => {
      this.#queryClient.invalidateQueries({ queryKey: ['todos'] })
    },
  }))
}

Callbacks passed per call to mutate only fire for the last call — mutateAsync gives you a promise per call instead, so you can wait for all of them when they succeed:

@Component({
  selector: 'todos',
  template: `
    <button (click)="handleAddAll(['Todo 1', 'Todo 2', 'Todo 3'])">Add all</button>
  `,
})
export class Todos {
  readonly #queryClient = inject(QueryClient)

  readonly addMutation = injectMutation(() => ({
    mutationFn: addTodo,
    onSuccess: () => this.#queryClient.invalidateQueries({ queryKey: ['todos'] }),
  }))

  async handleAddAll(todos: Array<string>) {
    try {
      await Promise.all(todos.map((todo) => this.addMutation.mutateAsync(todo)))
    } catch (error) {
      console.error('Failed to add todos:', error)
    }
  }
}

If some of the mutations above can fail independently of the others, and you want to know which ones did — rather than losing that information the moment the first one rejects — swap Promise.all for Promise.allSettled:

@Component({
  selector: 'todos',
  template: `
    <button (click)="handleAddAll(['Todo 1', 'Todo 2', 'Todo 3'])">Add all</button>
  `,
})
export class Todos {
  readonly #queryClient = inject(QueryClient)

  readonly addMutation = injectMutation(() => ({
    mutationFn: addTodo,
    onSuccess: () => this.#queryClient.invalidateQueries({ queryKey: ['todos'] }),
  }))

  async handleAddAll(todos: Array<string>) {
    const addResults = await Promise.allSettled(
      todos.map((todo) => this.addMutation.mutateAsync(todo)),
    )

    addResults.forEach((addResult, index) => {
      if (addResult.status === 'rejected') {
        console.error(`Failed to add "${todos[index]}":`, addResult.reason)
      }
    })
  }
}