In my Rails 7 app I've got data table which I want to decorate. The data comes from the API response so in fact it's an array of hashes. Like below:

# transactions_controller.rb

class TransactionsController < ApplicationController
  def index
    response = client.transactions.list(platform_id: current_user.platform_id, page: 1, per_page: 100)
    @transactions = response.body['data']
  end

  private

  def client
    @client ||= TestAPI::Client.new
  end
end

Now inside the transactions/index.html.erb I've got a table with @transactions data which I want to decorate:

#views/transactions/index.html.erb

<table >
  <thead>
    <tr>
      <b>
        <tr>
          <th>Date</th>
          <th>Amount</th>
        </tr>
      </b>
    </tr>
  </thead>

  <tbody>
    <% @transactions.map do |transaction| %>
      <tr>
        <td>
          <%= transaction['created_at'] %>
        </td>
        <td>
          <%= transaction['amount_cents'] %>
        </td>
      </tr>
    <% end %>
  </tbody>
</table>

I know I could inject that logic inside of view file to be like:

 (...)
        <td>
          <%= Date.parse(transaction['created_at']).strftime("%d.%m.%Y") %>
        </td>
        <td>
          <%= "#{ transactions_data.last['amount_cents']/100}" "#{ transactions_data.last['currency']}" %>
        </td>
(...)

But I want to get rid of that logic from the view since I'll have more and more logic in the future here.

CodePudding user response：

Kudos for wanting to remove logic from the view.

You need a new object, it could be called TransactionPresenter or whatever you choose. It will implement the view logic. So in your TransactionsController:

def index
    response = client.
                 transactions.
                 list(platform_id: current_user.platform_id, page: 1, per_page: 100).
                 map{|t| TransactionPresenter.new(t)}
    @transactions = response.body['data']
  end

and the TransactionPresenter model could be something like this:

class TransactionPresenter
  def initialize(transaction)
    # capture the fields of interest as variables
  end

  def amount
    "$#{amount_cents.to_f/100}" # for example, whatever makes sense in your context
  end
end

so all logic is removed from the view:

<table>
<% @transactions.each do |transaction| %>
  <tr><%= transaction.amount %></tr>
<% end %>
</table>