Method getFirstVisibleTime

src/service/ampdoc-impl.js:706–710

* Returns the time when the document has become visible for the first time. * If document has not yet become visible, the returned value is `null`. * @return {?time}

()

   * @return {?time}
   */
  getFirstVisibleTime() {
    return /** @type {?number} */ (
      this.signals_.get(AmpDocSignals_Enum.FIRST_VISIBLE)
    );
  }

  /**
   * Returns the time when the document has become visible for the last time.