What causes "parsing element tap options: %w" in grafana/k6?

Use an array for modifiers: tap({modifiers: ['Alt', 'Shift']}) or omit it

parsing element tap options

Error message

parsing element tap options: %w

What it means

Thrown synchronously when ElementHandle.tap cannot parse its options into ElementHandleTapOptions. The parser type-checks two fields via sobek ExportTo: position must export to map[string]float64 and modifiers must export to []string; everything else (force, noWaitAfter, timeout, trial) is coerced and unknown keys are ignored. So the error means position or modifiers has the wrong shape.

Solutions

Use an array for modifiers: tap({modifiers: ['Alt', 'Shift']}) or omit it
Express position as numeric {x, y} offsets from the element's top-left corner
Validate dynamically-built option objects before calling tap

Example fix

// before
await handle.tap({ modifiers: 'Shift' });
// after
await handle.tap({ modifiers: ['Shift'] });

Defensive patterns

Strategy: try-catch

Validate before calling

const modsOk = (m) => m == null || (Array.isArray(m) && m.every(x => typeof x === 'string'));
const posOk = (p) => p == null || (typeof p === 'object' && !Array.isArray(p) && Number.isFinite(p.x) && Number.isFinite(p.y));
if (!modsOk(opts?.modifiers) || !posOk(opts?.position)) {
  throw new Error('tap options: modifiers must be string[], position must be {x,y} numbers');
}
await handle.tap(opts);

Type guard

function isTapOptions(v) {
  return v == null || (
    (v.modifiers == null || (Array.isArray(v.modifiers) && v.modifiers.every(m => typeof m === 'string'))) &&
    (v.position == null || (Number.isFinite(v.position?.x) && Number.isFinite(v.position?.y)))
  );
}

Try / catch

try {
  await handle.tap(opts);
} catch (e) {
  if (String(e).includes('parsing element tap options')) {
    opts = { ...opts, modifiers: [opts.modifiers].flat().filter(Boolean), position: undefined };
    await handle.tap(opts);
  } else { throw e; }
}

Prevention

Write modifiers as arrays everywhere, even for a single key: ['Shift']
Keep position numeric {x, y}
Centralize tap/click option builders so shapes are validated once

When it happens

Trigger: tap({modifiers: 'Shift'}) — a string instead of an array; tap({position: {x: '0', y: 0}}) or tap({position: [10, 10]}) — position values not numeric object keys.

Common situations: Writing modifiers as a single string (common slip from keyboard API usage); passing CSS-like or array coordinates for position on touch-enabled pages tested via CDP.

Related errors

AI-assisted analysis of grafana/k6@3fcf5388d7 (2026-09-14). Data as JSON: /api/errors/faa7ee2b11c7cda2. Report an issue: GitHub.

Appendix: source

Thrown at internal/js/modules/k6/browser/browser/element_handle_mapping.go:253

			}), nil
		},
		"setInputFiles": func(files sobek.Value, opts sobek.Value) (*sobek.Promise, error) {
			popts, err := parseElementHandleSetInputFilesOptions(rt, opts, eh.DefaultTimeout())
			if err != nil {
				return nil, fmt.Errorf("parsing setInputFiles options: %w", err)
			}
			var pfiles common.Files
			if err := pfiles.Parse(vu.Context(), files); err != nil {
				return nil, fmt.Errorf("parsing setInputFiles parameter: %w", err)
			}
			return promise(vu, func() (any, error) {
				return nil, eh.SetInputFiles(&pfiles, popts) //nolint:wrapcheck
			}), nil
		},
		"tap": func(opts sobek.Value) (*sobek.Promise, error) {
			popts, err := parseElementHandleTapOptions(rt, opts, eh.Timeout())
			if err != nil {
				return nil, fmt.Errorf("parsing element tap options: %w", err)
			}
			return promise(vu, func() (any, error) {
				return nil, eh.Tap(popts) //nolint:wrapcheck
			}), nil
		},
		"textContent": func() *sobek.Promise {
			return promise(vu, func() (any, error) {
				s, ok, err := eh.TextContent()
				if err != nil {
					return nil, err //nolint:wrapcheck
				}
				if !ok {
					return nil, nil
				}
				return s, nil
			})
		},
		"type": func(text string, opts sobek.Value) (*sobek.Promise, error) {

View on GitHub (pinned to 3fcf5388d7)