code: function addGlowFilter(el) {
              if (!highlightFilter) {
                  highlightFilter = createFilterContainer(svg.select('.metadata-group'));
                  highlightFilterId = createGlowWithMatrix(highlightFilter);
              }
  
              let glowEl = d3Selection.select(el);
  
              glowEl
                  .style('stroke-width', highlightCircleActiveStrokeWidth)
                  .style('stroke-opacity', highlightCircleActiveStrokeOpacity)
                  .attr('filter', `url(#${highlightFilterId})`);
  
              bounceCircleHighlight(
                  glowEl,
                  ease,
                  highlightCircleActiveRadius
              );
          }
docs: Adds a filter to the element
  @param {DOMElement} el
  @private