Rails: Chartkick cummulative user graph

Question

I\'m using chartkick in an active admin dashboard and trying to track a cumulative user base over time.

Using groupdate to count by week I can successfully create a ch

Answer 1

If I understand your question, you need to manipulate the hash of data.

In controller do somehing like this:

@data = User.group_by_week(:created_at).count
accumulator = 0
@data.transform_values! do |val|
  val += accumulator
  accumulator = val
end

Then show the chart in view as <%= line_chart @data %>

If you inspect the hash <%= User.group_by_week(:created_at).count.inspect %> it becomes clear.

In order to use accumulator over any hash, could be useful to add a custom method to Class hash.

module HashPatch
  def accumulate_values!
    accumulator = 0
    transform_values! do |val|
      val+= accumulator
      accumulator = val
    end
  end
end
Hash.include HashPatch

points = {'x1' => 0, 'x2' => 10, 'x3' => 10, 'x4' => 10.1}
points.accumulate_values! #=> {"x1"=>0, "x2"=>10, "x3"=>20, "x4"=>30.1}

transform_values! since Ruby v4.2.1