Method flushLayoutShiftScore_

src/service/performance-impl.js:627–650

* Records the normalized CLS score, following the latest CWV standard. * See https://web.dev/evolving-cls/

()

   * See https://web.dev/evolving-cls/
   */
  flushLayoutShiftScore_() {
    const entries = this.layoutShiftEntries_;
    const old = this.metrics_.get(TickLabel_Enum.CUMULATIVE_LAYOUT_SHIFT);
    let union = 0;
    let sum = 0;
    for (const entry of entries) {
      if (entry.sources) {
        for (const source of entry.sources) {
          union |= getElementType(source.node);
        }
      }
      sum += entry.value;
    }
    entries.length = 0;
    this.recordGoogleFontExp_();
    if (old == null || sum > old) {
      // We'll record the largest windowed CLS.
      this.metrics_.reset(TickLabel_Enum.CUMULATIVE_LAYOUT_SHIFT);
      this.metrics_.reset(TickLabel_Enum.CUMULATIVE_LAYOUT_SHIFT_TYPE_UNION);
      this.tickDelta(TickLabel_Enum.CUMULATIVE_LAYOUT_SHIFT, sum);
      this.tickDelta(TickLabel_Enum.CUMULATIVE_LAYOUT_SHIFT_TYPE_UNION, union);
      this.flush();
    }
  }

  /**
   * Record the interaction to next paint score.