Method _getOrCreateElement

packages/platform-browser/src/browser/meta.ts:159–177

(
    meta: MetaDefinition,
    forceCreation: boolean = false,
  )

  }

  private _getOrCreateElement(
    meta: MetaDefinition,
    forceCreation: boolean = false,
  ): HTMLMetaElement {
    validateMetaDefinition(meta);
    if (!forceCreation) {
      const selector: string = parseSelector(meta);
      // It's allowed to have multiple elements with the same name so it's not enough to
      // just check that element with the same name already present on the page. We also need to
      // check if element has tag attributes
      const elem = this.getTags(selector).filter((elem) => containsAttributes(meta, elem))[0];
      if (elem !== undefined) return elem;
    }
    const element: HTMLMetaElement = this._dom.createElement('meta') as HTMLMetaElement;
    setMetaElementAttributes(meta, element);
    const head = this._doc.getElementsByTagName('head')[0];
    head.appendChild(element);
    return element;
  }
}

function buildMetaSelector(attrSelector: string): string {