grafana/k6 · error

unknown page on event: %q

Error message

unknown page on event: %q

What it means

Error "unknown page on event: %q" thrown in grafana/k6.

Source

Thrown at internal/js/modules/k6/browser/browser/page_mapping.go:792

	return func(eventName common.PageEventName, handle sobek.Callable) error {
		if handle == nil {
			panic(vu.Runtime().NewTypeError(`The "listener" argument must be a function`))
		}

		pageEvents := map[common.PageEventName]struct {
			mapp func(vu moduleVU, event common.PageEvent) mapping
			wait bool // Whether to wait for the handler to complete.
		}{
			common.PageEventConsole:         {mapp: mapConsoleMessage},
			common.PageEventMetric:          {mapp: mapMetricEvent, wait: true},
			common.PageEventRequest:         {mapp: mapRequestEvent},
			common.PageEventResponse:        {mapp: mapResponseEvent},
			common.PageEventRequestFinished: {mapp: mapRequestEvent},
			common.PageEventRequestFailed:   {mapp: mapRequestEvent},
		}
		pageEvent, ok := pageEvents[eventName]
		if !ok {
			return fmt.Errorf("unknown page on event: %q", eventName)
		}

		ctx := vu.Context()
		tq := vu.get(ctx, p.TargetID())

		return p.On(eventName, func(event common.PageEvent) error {
			wait := queueTask(ctx, tq, func() (sobek.Value, error) {
				_, err := handle(sobek.Undefined(), vu.Runtime().ToValue(pageEvent.mapp(vu, event)))
				if err != nil {
					return nil, fmt.Errorf("executing page.on('%s') handler: %w", eventName, err)
				}
				return nil, nil
			})
			if pageEvent.wait {
				if _, err := wait(); errors.Is(err, context.Canceled) {
					return errors.New("iteration ended before page.on handler completed executing")
				}
			}

View on GitHub (pinned to 93accf6570)

When it happens

Trigger: Thrown at internal/js/modules/k6/browser/browser/page_mapping.go:792 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/71ab7e58d2186866. Report an issue: GitHub.