Errors

Every error extends TenaceError and has a literal _tag, a stable code, and a name equal to the class name. Import them from @julr/tenace.

Class	_tag and code	Produced by	Fields
UnexpectedError	UnexpectedError, E_UNEXPECTED	any throw	cause: the thrown value
TimeoutError	TimeoutError, E_TIMEOUT	Timeout	timeoutMs
CircuitOpenError	CircuitOpenError, E_CIRCUIT_OPEN	Circuit breaker	state, retryAfterMs
BulkheadFullError	BulkheadFullError, E_BULKHEAD_FULL	Bulkhead	running, queued
RateLimitError	RateLimitError, E_RATE_LIMIT	Rate limit	key, retryAfterMs
LockNotAcquiredError	LockNotAcquiredError, E_LOCK_NOT_ACQUIRED	Lock	key
ChaosError	ChaosError, E_CHAOS	Chaos, thrown	none

UnexpectedError

UnexpectedError wraps anything your function threw. Its cause holds the raw value and its message copies the message of the cause. execute() rejects with the cause itself, and settle() returns the UnexpectedError. A failure inside a strategy that is not a bug, such as a lock provider that cannot reach Redis, is an UnexpectedError too.

CircuitOpenError

Field	Type	Description
state	'open' | 'half-open' | 'isolated'	The state of the circuit when it rejected the call.
retryAfterMs	number | undefined	When a new call may be admitted. undefined while isolated.

TenaceError

Member	Description
_tag	The literal discriminant of the error union.
code	A stable E_* identifier, for logs and serialization.
name	The class name. Not an enumerable field.
toJSON()	The tag, the code, the name, the message, the own enumerable fields, and the cause, without the stack.
new TenaceError(message, { cause })	The constructor of the subclasses.

instanceof TenaceError and isTenaceError(value) recognize errors from any copy of the package. instanceof on a subclass with a static readonly tag compares the tags, so it also works across copies. See Define an error.