Chartkick with Ruby on Rails to render a line_chart with multiple series

Question

I have a model Level that records level values from 8 different water boxes once every time that was defined. So, each level has a :box_id, a :level_value and a a :created_at timestamp. I would like to plot these values in a line_chart where y axis has the :created_at values for all boxes and the x axis has the levels. There will be 8 series with the level values registered along time.

I am using the Chartkick gem but I am not getting the right chart. My controller is this:

def chart
    @levels = Level.all
end

And I am trying to do this on my view:

<%= line_chart @levels.group(:box_id).group(:created_at).count %>

But I am getting this:

It seems that the problem is the count() method, but I did not find a way to do this without this method.

Answer 1

I found the answer by passing name and date to the line_chart.

This is the action on the controller:

def get_all_tanks_graph
    @hash = {}
    @array = Array.new
    @levels = Level.get_all_tanks_levels

    @levels.each do |l| 
      l.each do |i| 
        @hash[i.created_at] = i.level 
      end 
      @array << @hash 
      @hash = Hash.new 
    end

    render json: @array.each_with_index.map { 
      |a, index| { 
        name: "Caixa #{index + 1}", data: a 
      } 
    }

  end

This is the helper to call the action.

line_chart get_all_tanks_graph_path