grafana/k6 · error

setTimeout requires a >0 timeout parameter, received %.2f

Error message

setTimeout requires a >0 timeout parameter, received %.2f

What it means

Returned by ws.Socket.SetTimeout when the timeout parameter, converted from milliseconds, is <= 0 (the guard rejects d <= 0 after duration conversion). The value is reported with two decimals so fractional or negative inputs are visible. The callback is never scheduled and the socket's timer machinery is untouched.

Source

Thrown at internal/js/modules/k6/ws/ws.go:425

			Tags:   s.tagsAndMeta.Tags,
		},
		Time:     pongTimestamp,
		Metadata: s.tagsAndMeta.Metadata,
		Value:    metrics.D(pongTimestamp.Sub(pingTimestamp)),
	})
}

// SetTimeout executes the provided function inside the socket's event loop after at least the provided
// timeout, which is in ms, has elapsed
func (s *Socket) SetTimeout(fn sobek.Callable, timeoutMs float64) error {
	// Starts a goroutine, blocks once on the timeout and pushes the callable
	// back to the main loop through the scheduled channel.
	//
	// Intentionally not using the generic GetDurationValue() helper, since this
	// API is meant to use ms, similar to the original SetTimeout() JS API.
	d := time.Duration(timeoutMs * float64(time.Millisecond))
	if d <= 0 {
		return fmt.Errorf("setTimeout requires a >0 timeout parameter, received %.2f", timeoutMs)
	}
	go func() {
		select {
		case <-time.After(d):
			select {
			case s.scheduled <- fn:
			case <-s.done:
				return
			}

		case <-s.done:
			return
		}
	}()

	return nil
}

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Pass a positive millisecond value: socket.setTimeout(fn, 1000)
2. Guard dynamic values: socket.setTimeout(fn, Math.max(1, delay))

When it happens

Trigger: Thrown at internal/js/modules/k6/ws/ws.go:425 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/7fc604dac5b549ae. Report an issue: GitHub.