grafana/k6 · error

evaluate requires a page function

Error message

evaluate requires a page function

What it means

Error "evaluate requires a page function" thrown in grafana/k6.

Source

Thrown at internal/js/modules/k6/browser/browser/js_handle_mapping.go:24

	"github.com/grafana/sobek"

	"go.k6.io/k6/v2/internal/js/modules/k6/browser/common"
)

// mapJSHandle to the JS module.
func mapJSHandle(vu moduleVU, jsh common.JSHandleAPI) mapping {
	return mapping{
		"asElement": func() mapping {
			return mapElementHandle(vu, jsh.AsElement())
		},
		"dispose": func() *sobek.Promise {
			return promise(vu, func() (any, error) {
				return nil, jsh.Dispose()
			})
		},
		"evaluate": func(pageFunc sobek.Value, gargs ...sobek.Value) (*sobek.Promise, error) {
			if sobekEmptyString(pageFunc) {
				return nil, fmt.Errorf("evaluate requires a page function")
			}
			funcString := pageFunc.String()
			gopts := exportArgs(gargs)
			return promise(vu, func() (any, error) {
				return jsh.Evaluate(funcString, gopts...)
			}), nil
		},
		"evaluateHandle": func(pageFunc sobek.Value, gargs ...sobek.Value) (*sobek.Promise, error) {
			if sobekEmptyString(pageFunc) {
				return nil, fmt.Errorf("evaluateHandle requires a page function")
			}
			funcString := pageFunc.String()
			gopts := exportArgs(gargs)
			return promise(vu, func() (any, error) {
				h, err := jsh.EvaluateHandle(funcString, gopts...)
				if err != nil {
					return nil, err //nolint:wrapcheck
				}

View on GitHub (pinned to 93accf6570)

When it happens

Trigger: Thrown at internal/js/modules/k6/browser/browser/js_handle_mapping.go:24 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/ddce9654980d7813. Report an issue: GitHub.