code: function getCenterAndZoomTransformation(d3Node, config) {
      if (!d3Node) {
          return;
      }
  
      const { width, height, focusZoom } = config;
  
      return `
          translate(${width / 2}, ${height / 2})
          scale(${focusZoom})
          translate(${-d3Node.x}, ${-d3Node.y})
      `;
  }
docs: Returns the transformation to apply in order to center the graph on the
  selected node.
  @param {Object} d3Node - node to focus the graph view on.
  @param {Object} config - same as {@link #graphrenderer|config in renderGraph}.
  @returns {string} transform rule to apply.
  @memberof Graph/helper