private onScroll()

in src/app/shared/table-of-contents/table-of-contents.ts [151:174]

• 17 lines of code
• 6 McCabe index (conditional complexity)

  private onScroll(): void {
    const scrollOffset = this.getScrollOffset();
    let hasChanged = false;

    for (let i = 0; i < this._links.length; i++) {
      // A link is considered active if the page is scrolled past the
      // anchor without also being scrolled passed the next link.
      const currentLink = this._links[i];
      const nextLink = this._links[i + 1];
      const isActive = scrollOffset >= currentLink.top &&
                       (!nextLink || nextLink.top >= scrollOffset);

      if (isActive !== currentLink.active) {
        currentLink.active = isActive;
        hasChanged = true;
      }
    }

    if (hasChanged) {
      // The scroll listener runs outside of the Angular zone so
      // we need to bring it back in only when something has changed.
      this._ngZone.run(() => this._changeDetectorRef.markForCheck());
    }
  }