code: function _getNodeOpacity(node, highlightedNode, highlightedLink, config) {
      const highlight =
          node.highlighted ||
          node.id === (highlightedLink && highlightedLink.source) ||
          node.id === (highlightedLink && highlightedLink.target);
      const someNodeHighlighted = !!(
          highlightedNode ||
          (highlightedLink && highlightedLink.source && highlightedLink.target)
      );
      let opacity;
  
      if (someNodeHighlighted && config.highlightDegree === 0) {
          opacity = highlight ? config.node.opacity : config.highlightOpacity;
      } else if (someNodeHighlighted) {
          opacity = highlight ? config.node.opacity : config.highlightOpacity;
      } else {
          opacity = node.opacity || config.node.opacity;
      }
  
      return opacity;
  }
docs: Get the correct node opacity in order to properly make decisions based on context such as currently highlighted node.
  @param  {Object} node - the node object for whom we will generate properties.
  @param  {string} highlightedNode - same as {@link #graphrenderer|highlightedNode in renderGraph}.
  @param  {Object} highlightedLink - same as {@link #graphrenderer|highlightedLink in renderGraph}.
  @param  {Object} config - same as {@link #graphrenderer|config in renderGraph}.
  @returns {number} the opacity value for the given node.
  @memberof Graph/builder