createTask()

The createTask() function is the primary entry point for defining controlled asynchronous actions in ngx-task.

function createTask<TArgs, TResult>(
  handler: TaskHandler<TArgs, TResult>,
  options?: CreateTaskOptions<TArgs, TResult>,
): Task<TArgs, TResult>;

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Handler Function

The handler function receives arguments passed to .run(args) and a TaskContext object:

type TaskHandler<TArgs, TResult> = (
  args: TArgs,
  context: TaskContext,
) => Promise<TResult> | Observable<TResult>;

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Options (CreateTaskOptions)

Option	Type	Default	Description
concurrency	ConcurrencyPolicy	'drop'	Concurrency strategy: 'drop', 'restart', 'enqueue', 'latest', or { mode: 'parallel', limit?: number }.
timeout	number | TaskTimeoutOptions	undefined	Execution timeout in milliseconds (or object configuration).
pendingDelay	number	0	Delay in ms before pending signal becomes true. Prevents micro-flashes for fast operations.
minimumPendingDuration	number	0	Minimum time in ms pending signal remains true once activated.
classifyError	(err: unknown) => TaskError	Default classifier	Custom function to wrap and standardize thrown errors into TaskError.
destroyBehavior	'cancel' | 'detach' | 'allow'	'cancel'	Behavior when component containing task is destroyed.
injector	Injector	Current context	Custom Angular Injector for tasks instantiated outside injection context.
maxQueueSize	number	Infinity	Maximum queue size for queued policies (enqueue, parallel).
overflowPolicy	QueueOverflowPolicy	'reject-newest'	Overflow handling when queue is full ('reject-newest', 'drop-oldest', 'throw').
observableResult	ObservableResultPolicy	'latest'	Result resolution strategy for Observable handlers ('latest', 'first', 'last', 'forbid-multiple').

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Example Usage

const userTask = createTask(
  async (userId: string, { signal, reportProgress }) => {
    reportProgress({ loaded: 0, total: 100, percentage: 0 });
    const user = await fetchUser(userId, { signal });
    reportProgress({ loaded: 100, total: 100, percentage: 100 });
    return user;
  },
  {
    concurrency: 'restart',
    timeout: 5000,
    pendingDelay: 200,
    minimumPendingDuration: 500,
  },
);