grafana/k6 · warning

unexpected value %v of type %T

Error message

unexpected value %v of type %T

What it means

count() expects the evaluation to return a JS number (deserialized as float64). Any other type — string, nil, object — triggers this error; the injected count script broke its contract or the context died.

Source

Thrown at internal/js/modules/k6/browser/common/element_handle.go:767

	eopts := evalOptions{
		forceCallable: true,
		returnByValue: true,
	}
	result, err := h.evalWithScript(
		apiCtx,
		eopts, fn, parsedSelector,
	)
	if err != nil {
		return 0, err
	}
	switch r := result.(type) {
	case float64:
		if r < float64(math.MinInt32) || r > float64(math.MaxInt32) {
			return 0, fmt.Errorf("value %v out of range for int32 type", r)
		}
		return int(r), nil
	default:
		return 0, fmt.Errorf("unexpected value %v of type %T", r, r)
	}
}

// findFrameNavigationIndex finds the index of the first internal:control=enter-frame directive
func (h *ElementHandle) findFrameNavigationIndex(selector *Selector) int {
	for i, part := range selector.Parts {
		if part.Name == "internal:control" && part.Body == "enter-frame" {
			return i
		}
	}
	return -1
}

// splitSelectorAtFrame splits a selector at the frame navigation boundary
func (h *ElementHandle) splitSelectorAtFrame(selector *Selector, frameIndex int) (*Selector, *Selector) {
	beforeFrame := &Selector{
		Selector: selector.Selector, // Keep original for reference
		Parts:    selector.Parts[:frameIndex],

View on GitHub (pinned to 93accf6570)

Solutions

1. Retry after the page settles
2. Upgrade to a matching k6 build
3. Report a minimal reproduction if it persists

try {
  const n = await handle.count(sel);
} catch (e) {
  if (String(e).includes('unexpected value')) {
    await handle.count(sel); // one retry with settled context
  } else { throw e; }
}

When it happens

Trigger: handle.count(selector) when the eval returns undefined (execution context destroyed) or a non-numeric value from a mismatched injected script.

Common situations: Navigation racing the count; custom builds with stale injected script; rare on stock releases.

Related errors

• value %v out of range for int32 type
• unexpected type %T
• checking element is in viewport: unexpected type %T
• converting result (%v of type %t) to border: %w
• waiting for states %v of element %q

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/92f542c827d6728b. Report an issue: GitHub.