grafana/k6 · error

parsing element handle click option modifiers: %w

Error message

parsing element handle click option modifiers: %w

What it means

k6 browser's parseElementHandleClickOptions converts the JavaScript `modifiers` click option into a Go []string via rt.ExportTo. ExportTo fails when the Sobek value is not exportable as a string array (e.g. a string, number, or object), so k6 wraps the failure as 'parsing element handle click option modifiers'. Modifiers must be an array of key names such as 'Alt', 'Control', 'Meta', or 'Shift'.

Source

Thrown at internal/js/modules/k6/browser/browser/element_handle_mapping.go:609

	err := parseElementHandleBasePointerOptions(&ehcopts.ElementHandleBasePointerOptions, rt, opts)
	if err != nil {
		return ehcopts, err
	}

	obj := opts.ToObject(rt)
	for _, k := range obj.Keys() {
		switch k {
		case "button":
			ehcopts.Button = obj.Get(k).String()
		case "clickCount":
			ehcopts.ClickCount = obj.Get(k).ToInteger()
		case "delay":
			ehcopts.Delay = obj.Get(k).ToInteger()
		case "modifiers":
			var m []string
			if err := rt.ExportTo(obj.Get(k), &m); err != nil {
				return ehcopts, fmt.Errorf("parsing element handle click option modifiers: %w", err)
			}
			ehcopts.Modifiers = m
		}
	}
	return ehcopts, nil
}

// parseElementHandleBasePointerOptions parses the element handle base pointer options from a
// Sobek value into o.
func parseElementHandleBasePointerOptions(
	o *common.ElementHandleBasePointerOptions, rt *sobek.Runtime, opts sobek.Value,
) error {
	if k6common.IsNullish(opts) {
		return nil
	}

	if err := parseElementHandleBaseOptions(&o.ElementHandleBaseOptions, rt, opts); err != nil {
		return err

View on GitHub (pinned to 8d06114777)

Solutions

1. Pass modifiers as an array of strings, e.g. { modifiers: ['Shift'] }
2. Verify the value type with Array.isArray(opts.modifiers) before calling click
3. Check each element is a string (filter with typeof m === 'string')
4. Remove the modifiers option entirely if not needed (it is optional)

Example fix

// before
await page.click('#submit', { modifiers: 'Shift' });

// after
await page.click('#submit', { modifiers: ['Shift'] });

const MODIFIERS = ['Alt', 'Control', 'Meta', 'Shift'];
function validModifiers(opts) {
  return opts == null || opts.modifiers === undefined ||
    (Array.isArray(opts.modifiers) && opts.modifiers.every(m => typeof m === 'string' && MODIFIERS.includes(m)));
}

function isStringArray(v) {
  return Array.isArray(v) && v.every(x => typeof x === 'string');
}

try {
  await page.click(sel, { modifiers: ['Shift'] });
} catch (e) {
  if (String(e).includes('parsing element handle click option modifiers')) {
    throw new Error('modifiers must be an array of strings, e.g. [\'Shift\']: ' + e);
  }
  throw e;
}

When it happens

Trigger: Calling page.click or elementHandle.click with options where `modifiers` is not an array of strings: e.g. modifiers: 'Shift' (bare string), modifiers: 5, modifiers: {0:'Shift'} as a non-array object, or an array containing non-string elements that Sobek cannot export to []string.

Common situations: Copy-pasting Playwright snippets that pass a single modifier string instead of an array; building the modifiers array dynamically and accidentally producing a non-array; typos that assign another option's value to modifiers; template literals producing a string instead of an array.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• predicate function is not callable
• steps must be an integer, got %s
• missing required argument 'url'
• parsing click options: %w
• parsing waitForFunction options: %w

AI-assisted analysis of grafana/k6@8d06114777 (2026-09-14). Data as JSON: /api/errors/a177973ace905741. Report an issue: GitHub.