Method isObserved

testing/intersection-observer-stub.js:41–48

* @param {!Element} target * @param {{ * root: (!Document|!Element|undefined), * rootMargin: (string|undefined), * thresholds: (number|!Array |undefined), * }=} options * @return {boolean}

(target, options = {})

   * @return {boolean}
   */
  isObserved(target, options = {}) {
    return Array.from(this.observers).some((observer) => {
      if (!observer.elements.has(target)) {
        return false;
      }
      return matchesObserver(observer, options);
    });
  }

  /**
   * @param {!IntersectionObserverEntry|!Array<IntersectionObserverEntry>} entryOrEntries