grafana/k6 · error

parsing select option values: %w

Error message

parsing select option values: %w

What it means

Thrown when the values argument of locator.selectOption(values, opts) cannot be converted by ConvertSelectOptionValues. Accepted shapes: null/undefined (select nothing... actually returns no options), a plain string (matches value or label), an array of strings and/or descriptor objects {value?: string, label?: string, index?: number}, a single descriptor object, an ElementHandle pointing at an <option>, or a sobek object with value/label/index getters. Any other type or malformed descriptor produces 'parsing select option values: %w' wrapping a specific cause (see errors 495-499).

Source

Thrown at internal/js/modules/k6/browser/browser/locator_mapping.go:362

			}), nil
		},
		"inputValue": func(opts sobek.Value) (*sobek.Promise, error) {
			copts := common.NewFrameInputValueOptions(lo.Timeout())
			if err := copts.Parse(vu.Context(), opts); err != nil {
				return nil, fmt.Errorf("parsing input value options: %w", err)
			}
			return promise(vu, func() (any, error) {
				return lo.InputValue(copts) //nolint:wrapcheck
			}), nil
		},
		"selectOption": func(values sobek.Value, opts sobek.Value) (*sobek.Promise, error) {
			copts := common.NewFrameSelectOptionOptions(lo.Timeout())
			if err := copts.Parse(vu.Context(), opts); err != nil {
				return nil, fmt.Errorf("parsing select option options: %w", err)
			}
			convValues, err := ConvertSelectOptionValues(vu.Runtime(), values)
			if err != nil {
				return nil, fmt.Errorf("parsing select option values: %w", err)
			}
			return promise(vu, func() (any, error) {
				return lo.SelectOption(convValues, copts) //nolint:wrapcheck
			}), nil
		},
		"press": func(key string, opts sobek.Value) (*sobek.Promise, error) {
			copts := common.NewFramePressOptions(lo.Timeout())
			if err := copts.Parse(vu.Context(), opts); err != nil {
				return nil, fmt.Errorf("parsing press options: %w", err)
			}
			return promise(vu, func() (any, error) {
				return nil, lo.Press(key, copts) //nolint:wrapcheck
			}), nil
		},

		"pressSequentially": func(text string, opts sobek.Value) (*sobek.Promise, error) {
			copts := common.NewFrameTypeOptions(lo.Timeout())
			if err := copts.Parse(vu.Context(), opts); err != nil {

View on GitHub (pinned to 93accf6570)

Solutions

1. Wrap numeric selection in a descriptor: selectOption({ index: 2 }) instead of selectOption(2)
2. Ensure every array item is a string or an object with only string value/label and numeric index
3. Sanitize external data before passing it: map values to strings or descriptors
4. Pass an ElementHandle only when it references an actual <option> element

Example fix

// before
await page.locator('select').selectOption([0, 2]);

// after
await page.locator('select').selectOption([{ index: 0 }, { index: 2 }]);

function normalizeSelectValues(values) {
  if (values === null || values === undefined) return values;
  if (typeof values === 'string') return values;
  if (Array.isArray(values)) {
    return values
      .filter((v) => v !== null && v !== undefined)
      .map((v) => {
        if (typeof v === 'string') return v;
        if (typeof v === 'number') return { index: v };
        if (typeof v === 'object') {
          const o = {};
          if ('value' in v) o.value = String(v.value);
          if ('label' in v && v.label !== null) o.label = String(v.label);
          if ('index' in v) o.index = Number(v.index);
          return o;
        }
        throw new TypeError(`Unsupported selectOption item: ${typeof v}`);
      });
  }
  if (typeof values === 'object') return { value: String(values.value ?? ''), label: values.label !== undefined ? String(values.label) : undefined };
  throw new TypeError(`Unsupported selectOption values type: ${typeof values}`);
}

function isSelectOptionValues(v) {
  if (v === null || v === undefined || typeof v === 'string') return true;
  if (Array.isArray(v)) return v.every((item) =>
    typeof item === 'string' ||
    (typeof item === 'object' && item !== null &&
      (item.value === undefined || typeof item.value === 'string') &&
      (item.label === undefined || typeof item.label === 'string') &&
      (item.index === undefined || typeof item.index === 'number')));
  if (typeof v === 'object') {
    return (v.value === undefined || typeof v.value === 'string') &&
           (v.label === undefined || typeof v.label === 'string') &&
           (v.index === undefined || typeof v.index === 'number');
  }
  return false;
}

try {
  await locator.selectOption(values, opts);
} catch (e) {
  if (/parsing select option values/.test(String(e.message))) {
    throw new Error(`Invalid selectOption values: ${JSON.stringify(values)} (${e.message})`);
  }
  throw e;
}

When it happens

Trigger: selectOption(42) or selectOption(true) — unsupported scalar kind; selectOption([1, 2]) — array items that are neither string nor object; selectOption({ value: 2 }) — descriptor value/label not a string; selectOption(['a', null]) — null item in array.

Common situations: Passing numbers (option indices) directly instead of { index: n } descriptors; data-driven scripts feeding unvalidated API/JSON data into selectOption; assuming Playwright's SelectOption class objects work in k6.

Related errors

• parsing select option options: %w
• options: expected array, got %T
• options: expected string or object, got %T
• options: expected object, got %T
• options: unsupported type %T

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/aae94d3b4965de84. Report an issue: GitHub.