Reference

This section documents the public classes exported from @haskou/flow.

The main API is organized around async tasks: concurrency, timing, retries, dependency protection, fallback resolution, and composition.

Numeric time arguments are interpreted as milliseconds unless a page says otherwise. Most time options also accept Duration from @haskou/value-objects.

Concurrency

Class	Purpose
Semaphore	Limit concurrent access to a shared capacity.
SemaphorePermit	Release handle returned by Semaphore.acquire().
Queue	Run submitted tasks with bounded concurrency.
QueueOptions	Configure queue concurrency.

Timing

Class	Purpose
RateLimiter	Space queued task starts by a fixed interval.
RateLimiterOptions	Configure rate limiter interval and queue behavior.
Timeout	Reject work that does not finish before a timeout.
Scheduler	Run periodic non-overlapping jobs.
SchedulerOptions	Configure scheduler interval, task, policy, and semaphore.
SchedulerErrorPolicy	Enum-style policy for scheduler task failures.
Debouncer	Collapse repeated calls into the latest task after a quiet period.
Throttler	Run tasks one at a time with a minimum interval between starts.

Resilience

Class	Purpose
CircuitBreaker	Reject work after repeated failures and probe recovery later.
CircuitBreakerOptions	Configure thresholds, recovery timeout, and half-open concurrency.
CircuitBreakerState	Enum-style state object for circuit breaker state.
Retrier	Retry failing tasks with configured attempts and optional delay.
RetryOptions	Configure retry attempts and delay.

Configuration values

These classes are optional. Use them when you want named configuration objects instead of passing numbers directly.

Class	Purpose
Concurrency	Positive-integer concurrency limit used by queues and half-open circuit breaker probes.
SemaphoreCapacity	Positive-integer semaphore capacity.
CircuitBreakerFailureThreshold	Positive-integer failure threshold.
CircuitBreakerRecoveryTimeout	Positive-integer recovery timeout.
CircuitBreakerSuccessThreshold	Positive-integer half-open success threshold.
RateLimiterInterval	Positive-integer rate-limit interval.
SchedulerInterval	Positive-integer scheduler interval.
DebounceDelay	Positive-integer debounce delay.
ThrottleInterval	Positive-integer throttle interval.
RetryAttempts	Positive-integer retry attempts.
RetryDelay	Non-negative retry delay.
TimeoutDuration	Positive-integer timeout duration.

Fallbacks and composition

Class	Purpose
Flow	Fluent builder for task, timeout, retry, limit, abortability, and existing async controls.
Racer	Run multiple candidates and resolve with the first success.
Abortable	Abort running flow work through an AbortSignal.
FallbackChain	Resolve a value from ordered fallback sources.
FallbackAttempt	One fallback source inside a chain.
FlowPipeline	Lower-level composition for classes that expose run(task).

Errors

See Errors for the full error list and when each one is thrown.