v10/packages/html/src/define/tests/safe-define.test.ts

import { afterEach, describe, expect, it, vi } from 'vitest';
import { safeDefine } from '../safe-define';

describe('safeDefine', () => {
  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it('registers a custom element', () => {
    class TestElement extends HTMLElement {
      static tagName = 'test-sd-register';
    }

    expect(customElements.get('test-sd-register')).toBeUndefined();
    safeDefine(TestElement);
    expect(customElements.get('test-sd-register')).toBe(TestElement);
  });

  it('does not throw when element is already registered', () => {
    class TestElement extends HTMLElement {
      static tagName = 'test-sd-no-throw';
    }

    customElements.define('test-sd-no-throw', TestElement);
    expect(() => safeDefine(TestElement)).not.toThrow();
  });

  it('does not replace an existing registration', () => {
    class Original extends HTMLElement {
      static tagName = 'test-sd-no-replace';
    }
    class Replacement extends HTMLElement {
      static tagName = 'test-sd-no-replace';
    }

    safeDefine(Original);
    safeDefine(Replacement);
    expect(customElements.get('test-sd-no-replace')).toBe(Original);
  });

  it('does nothing when customElements is unavailable', () => {
    vi.stubGlobal('customElements', undefined);

    class TestElement extends HTMLElement {
      static tagName = 'test-sd-ssr';
    }

    expect(() => safeDefine(TestElement)).not.toThrow();
  });
});