code: function drawGridLines() {
              let scale = isHorizontal ? xScale : yScale;
  
              svg.select('.grid-lines-group')
                  .selectAll('line')
                  .remove();
  
              if (grid === 'horizontal' || grid === 'full') {
                  svg.select('.grid-lines-group')
                      .selectAll('line.horizontal-grid-line')
                      .data(scale.ticks(yTicks).slice(1))
                      .enter()
                        .append('line')
                          .attr('class', 'horizontal-grid-line')
                          .attr('x1', (-xAxisPadding.left + 1))
                          .attr('x2', chartWidth)
                          .attr('y1', (d) => yScale(d))
                          .attr('y2', (d) => yScale(d));
              }
  
              if (grid === 'vertical' || grid === 'full') {
                  svg.select('.grid-lines-group')
                      .selectAll('line.vertical-grid-line')
                      .data(scale.ticks(xTicks).slice(1))
                      .enter()
                        .append('line')
                          .attr('class', 'vertical-grid-line')
                          .attr('y1', 0)
                          .attr('y2', chartHeight)
                          .attr('x1', (d) => xScale(d))
                          .attr('x2', (d) => xScale(d));
              }
  
              if (isHorizontal) {
                  drawVerticalExtendedLine();
              } else {
                  drawHorizontalExtendedLine();
              }
          }
docs: Draws grid lines on the background of the chart
  @return void