         .attr('class', (d, i) -> "target target#{i}")
         .call(observe_mouse)
 
-    if params.drawNullAsZero
-      filter_scatter_values = _.identity
-    else
-      filter_scatter_values = (values) ->
-        _.filter values, (d) -> d.value?
-
 
     if type is 'line'
       target.append("path")

        else
          area

    transform_value =
      if params.drawNullAsZero
        (v) -> v ? 0
      else
        (v) -> v

    time_min = null
    time_max = null

          .style('stroke-opacity', line_opacity)
          .attr('fill', (d, i) -> if line_mode(d, i) is 'area' then color i)
          .style('fill-opacity', area_opacity)
          .attr('d', (d, i) -> line_fn(d, i)(expand_line_values(d.values)))
    else if type is 'scatter'
      target.selectAll('circle')
          .data((d) -> filter_scatter_values d.values)
