angular/components · warning

Violations found on element: %o:

Error message

Violations found on element: %o:

What it means

This is a dev-time accessibility reporting helper from the Aria package: when element checkers find ARIA violations, reportViolations logs them to the console. Note that despite the message text, the implementation uses console.warn, not console.error.

Source

Thrown at src/aria/private/utils/violations.ts:12

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */

/** Logs each of the violations to the console as errors, optionally with the host element context. */
export function reportViolations(violations: string[], element: Element): void {
  if (violations.length) {
    console.warn('Violations found on element: %o:', element);
    violations.forEach(violation => {
      console.warn(violation);
    });
  }
}

View on GitHub (pinned to 0411926e7d)

Solutions

1. Read the logged violation strings and the %o element reference to find the offending host element
2. Fix the underlying ARIA issue the violation describes (add required attributes/roles)
3. If these are third-party component warnings, suppress in production by ensuring checks only run in dev mode

const violations = checkAria(element);
if (violations.length) reportViolations(violations, element); // only call when you expect to report

function hasNoViolations(v: string[]): v is [] { return v.length === 0; }

When it happens

Trigger: An element is validated (e.g. by an Aria umbrella/disabled checker calling reportViolations from its constructor) and the violations array is non-empty, so each violation string plus the host element is logged.

Common situations: Running the Aria accessibility checkers on elements with missing ARIA attributes (e.g. disabled elements without aria-disabled wiring); seeing this during development with strict a11y checks enabled.

Related errors

• Detected a matBadge on an "aria-hidden" "<mat-icon>". Consid
• Cannot retrieve popup content because the combobox is closed
• Maps event target that uses native events must have `addEven
• Unsupported MatButton appearance "${appearance}"
• A mat-tab-nav-panel must be specified via [tabPanel].

AI-assisted analysis of angular/components@0411926e7d (2026-08-31). Data as JSON: /api/errors/84abb97a6b9640ea. Report an issue: GitHub.