Errors

All library-specific errors extend FlowError. FlowError is an abstract base class; concrete failures are represented by one class per error.

Import

import {
  CircuitBreakerOpenError,
  FallbackChainExhaustedError,
  SchedulerAlreadyRunningError,
} from '@haskou/flow';

Signature

abstract class FlowError extends Error

Error list

Error	Thrown by	Meaning
SemaphoreReleasedError	SemaphorePermit.release()	A permit was released more than once.
QueueClearedError	Queue.clear()	Pending queue work was cleared before it started.
CircuitBreakerOpenError	CircuitBreaker.execute(), CircuitBreaker.run()	The breaker rejected execution because it is open or half-open concurrency is full.
FlowCancelledError	Debouncer.cancel()	Pending debounce work was cancelled.
FlowAbortedError	Abortable.run(), Flow.abortable()	Running work was aborted.
FlowTaskMissingError	Flow.run()	No task was configured before running the flow.
FallbackChainExhaustedError	FallbackChain.run()	No fallback attempt produced a value.
TimeoutError	Timeout.run(), Flow.timeout()	Work exceeded its configured timeout.
RacerExhaustedError	Racer.run()	No racer candidate produced a successful value.
SchedulerAlreadyRunningError	Scheduler.assertStopped()	The scheduler is running when stopped state is required.
InvalidSemaphorePermitsError	Semaphore	Permits must be a positive integer.
InvalidQueueConcurrencyError	QueueOptions	Queue concurrency must be a positive integer.
InvalidRateLimiterIntervalError	RateLimiterOptions	Rate limiter interval must be a positive integer.
InvalidSchedulerIntervalError	SchedulerOptions	Scheduler interval must be a positive integer.
InvalidDebouncerDelayError	Debouncer	Debounce delay must be a positive integer.
InvalidThrottlerIntervalError	Throttler	Throttle interval must be a positive integer.
InvalidTimeoutDurationError	Timeout	Timeout duration must be a positive integer.
InvalidRetryAttemptsError	RetryOptions	Retry attempts must be a positive integer.
InvalidRetryDelayError	RetryOptions	Retry delay must be a non-negative integer.
InvalidCircuitBreakerFailureThresholdError	CircuitBreakerOptions	Failure threshold must be a positive integer.
InvalidCircuitBreakerRecoveryTimeoutError	CircuitBreakerOptions	Recovery timeout must be a positive integer.
InvalidCircuitBreakerSuccessThresholdError	CircuitBreakerOptions	Success threshold must be a positive integer.
InvalidCircuitBreakerHalfOpenMaxConcurrentError	CircuitBreakerOptions	Half-open max concurrency must be a positive integer.

Example

import { CircuitBreakerOpenError } from '@haskou/flow';

try {
  await circuitBreaker.run(() => callProvider());
} catch (error) {
  if (error instanceof CircuitBreakerOpenError) {
    // Dependency is currently protected by the breaker.
  }
}

Validation notes

Numeric configuration values are validated before they are stored. When a value is invalid, the public constructor throws the error class that belongs to that option, such as InvalidTimeoutDurationError or InvalidRetryAttemptsError.

Related

• Reference overview
• CircuitBreaker
• Debouncer
• FallbackChain