[LRUG] [Help request] Programmatically inserting user data into js chart

[Craig R Webster]

Hi Jesse,

Are you able to write a test that shows what you’d like to do? This usually helps me when I’m not sure how to proceed.

This is roughly what you want to do, written in RSpec:

  describe Favorite do
    describe '#to_data_array' do
      let(:subject) { Favourite.new numbers: '1,3,4,5,7' }

      it “returns the structure that I expect” do
        expected_value = [
          { key: 0, value: 1 },
          { key: 1, value: 3 },
          { key: 2, value: 4 },
          { key: 3, value: 5 },
          { key: 4, value: 7 }
        ]
        expect(subject.to_data_array).to eql expected_value
      end
    end
  end

You should then be able to implement the code to make the tests pass - something like this maybe:

  class Favourite
    def to_data_array
      numbers.split(',').each_with_object([]).with_index do |(number, result), index|
        result << { key: index, value: number }
      end
    end
  end

Running the tests will tell you if you got the implementation like you’d want it. You can now do this in the controller:

  @jsonish = JSON.pretty_generate @favorite.to_data_array

Yours,
Craig | http://barkingiguana.com/
--
Barking Iguana Ltd. is a company registered in England and Wales.
Registered number: 08915147. Registered address: Jubilee House, East Beach, Lytham, St. Annes, Lancashire, England, FY8 5FT.

> On 8 Jun 2016, at 14:32, Jesse Waites <jesse.waites at gmail.com> wrote:
> 
> Hi everyone,
> 
> I spun up a new Rails app to experiment with the D3 charting library and hit a minor snag. I've never done anything like the before so I want to make sure I do it the "best" way possible and not some hacky way, which I could certainly come up with, ha.
> 
> Here's the situation:
> 
> I have a new Rails app with 1 model, view, and controller called "Favorites"
> A user would add favorite colors, favorite movie, and favorite numbers, in 3 different form fields, each as a string.
> 
> In the controller, I remap the numbers string into  a proper array with integers.
> 
> @data = @favorite.numbers.split(",").map { |s| s.to_i }
> 
> At this point, lets say @data is now an array of [5,4,3,2,1] - We know the length of this array and the contents.
> 
> On the show page, in the view, I have a variable called dataset that the hardcoded 
> D3 chart is working off of. Here is a jsfiddle of the exact chart I am trying to get to work with user data.
> 
> http://jsfiddle.net/enigmarm/3HL4a/13/
> 
> 
> var dataset = [
> 	{ key: 0, value: 5 },
> 	{ key: 1, value: 10 },
> 	{ key: 2, value: 13 },
> 	{ key: 3, value: 19 },
> 	{ key: 4, value: 21 },
> 	{ key: 5, value: 25 },
> 	{ key: 6, value: 22 },
> 	{ key: 7, value: 18 },
> 	{ key: 8, value: 15 },
> 	{ key: 9, value: 13 },
> 	{ key: 10, value: 11 },
> 	{ key: 11, value: 12 },
> 	{ key: 12, value: 15 },
> 	{ key: 13, value: 20 },
> 	{ key: 14, value: 18 },
> 	{ key: 15, value: 17 },
> 	{ key: 16, value: 16 },
> 	{ key: 17, value: 18 },
> 	{ key: 18, value: 23 },
> 	{ key: 19, value: 25 } ];
> 
> So I need to iterate over my array, put the index into the "key" position, and put the value into the "value" section. If the array had 2 elements, I need to do it twice. 5 elements, 5 times.
> 
> I wrote a stupid method called "make jsonish" that isnt working:
> 
> def make_jsonish(array)
>       array.each_with_index do |num, i|
>         puts "{ key: #{i}, value: #{num}},"
>       end
>     end
> 
> I don't think the "puts" thing will work anyway. I'm a bit stumped as to how to best do this so I would appreciate any help.
> 
> Here is a gist of the view:
> 
> https://gist.github.com/piratebroadcast/19b2ca6617343d8812d2a40325f76bc7
> 
> Controller gist:
> 
> https://gist.github.com/piratebroadcast/ce802346d75e667fface711f8dfc17e0
> 
> 
> Anyone have any suggestions as to how I should move forward with this? Seems like a simple thing but I can't quite sort it out by myself.
> 
> 
> Thank you!!!
> 
> 
> 
> 
> 
> -- 
> Jesse Waites
> JesseWaites.com
> <Screen Shot 2016-06-07 at 11.05.41 AM.png>_______________________________________________
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