grafana/k6 · error

the body is null so we can't transform it to HTML - this lik

Error message

the body is null so we can't transform it to HTML - this likely was because of a request error getting the response

What it means

Response.HTML() was called on a response whose Body is nil. The body is null when the request errored before a body could be read (network failure, timeout, or a throw on status), so there is nothing to parse into an html.Selection. Also surfaces indirectly via SubmitForm/ClickLink, which call HTML() internally.

Source

Thrown at js/modules/k6/http/response.go:44

	validatedJSON bool
}

type jsonError struct {
	line      int
	character int
	err       error
}

func (j jsonError) Error() string {
	errMessage := "cannot parse json due to an error at line"
	return fmt.Sprintf("%s %d, character %d , error: %v", errMessage, j.line, j.character, j.err)
}

// HTML returns the body as an html.Selection
func (res *Response) HTML(selector ...string) html.Selection {
	rt := res.client.moduleInstance.vu.Runtime()
	if res.Body == nil {
		err := fmt.Errorf("the body is null so we can't transform it to HTML" +
			" - this likely was because of a request error getting the response")
		common.Throw(rt, err)
	}

	body, err := common.ToString(res.Body)
	if err != nil {
		common.Throw(rt, err)
	}

	sel, err := html.ParseHTML(rt, body)
	if err != nil {
		common.Throw(rt, err)
	}
	sel.URL = res.URL
	if len(selector) > 0 {
		sel = sel.Find(selector[0])
	}
	return sel

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Check res.error / res.status or res.Body != null before calling res.html()
2. Fix the underlying request error (URL, timeout, connectivity) so a real body is returned

When it happens

Trigger: Thrown at js/modules/k6/http/response.go:44 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/d29934e0abc6c8c4. Report an issue: GitHub.