microsoft/playwright · error · Error

"${name}" engine expects a selector list and optional maximu

Error message

"${name}" engine expects a selector list and optional maximum distance in pixels

What it means

Error ""${name}" engine expects a selector list and optional maximum distance in pixels" thrown in microsoft/playwright.

Source

Thrown at packages/injected/src/selectorEvaluator.ts:514

const hasTextEngine: SelectorEngine = {
  matches(element: Element, args: (string | number | Selector)[], context: QueryContext, evaluator: SelectorEvaluator): boolean {
    if (args.length !== 1 || typeof args[0] !== 'string')
      throw new Error(`"has-text" engine expects a single string`);
    if (shouldSkipForTextMatching(element))
      return false;
    const text = normalizeWhiteSpace(args[0]).toLowerCase();
    const matcher = (elementText: ElementText) => elementText.normalized.toLowerCase().includes(text);
    return matcher(elementText((evaluator as SelectorEvaluatorImpl)._cacheText, element));
  },
};

function createLayoutEngine(name: LayoutSelectorName): SelectorEngine {
  return {
    matches(element: Element, args: (string | number | Selector)[], context: QueryContext, evaluator: SelectorEvaluator): boolean {
      const maxDistance = args.length && typeof args[args.length - 1] === 'number' ? args[args.length - 1] : undefined;
      const queryArgs = maxDistance === undefined ? args : args.slice(0, args.length - 1);
      if (args.length < 1 + (maxDistance === undefined ? 0 : 1))
        throw new Error(`"${name}" engine expects a selector list and optional maximum distance in pixels`);
      const inner = evaluator.query(context, queryArgs);
      const score = layoutSelectorScore(name, element, inner, maxDistance);
      if (score === undefined)
        return false;
      (evaluator as SelectorEvaluatorImpl)._markScore(element, score);
      return true;
    }
  };
}

const nthMatchEngine: SelectorEngine = {
  query(context: QueryContext, args: (string | number | Selector)[], evaluator: SelectorEvaluator): Element[] {
    let index = args[args.length - 1];
    if (args.length < 2)
      throw new Error(`"nth-match" engine expects non-empty selector list and an index argument`);
    if (typeof index !== 'number' || index < 1)
      throw new Error(`"nth-match" engine expects a one-based index as the last argument`);
    const elements = isEngine.query!(context, args.slice(0, args.length - 1), evaluator);

View on GitHub (pinned to c8fc3bf8d3)

When it happens

Trigger: Thrown at packages/injected/src/selectorEvaluator.ts:514 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/8bd898c3bb5a0d47. Report an issue: GitHub.