One of the most primitive things you do when coding is writing if-else conditionals.

When I just started, this looked perfect to me:

1. 2015: If-Elsif # 

# app/models/task.rb
class Task < ApplicationRecord
  def status_color(status)
    if status == 'incoming'
      'grey'
    elsif status == 'todo'
      'orange'
    elsif status == 'done'
      'green'
    elsif status == 'spam' || status == "error"
      'red'
    else
      'black'
    end
  end
end

Task.status_color('done')
=> 'green'

One beautiful day, I learnt about Rubocop and it introduced me to case-when

2. 2017: Case-When # 

# app/models/task.rb
class Task < ApplicationRecord
  def status_color(status)
    case status
    when 'incoming'
      'grey'
    when 'todo'
      'orange'
    when 'done'
      'green'
    when 'spam', 'error'
      'red'
    else
      'black'
    end
  end
end

Task.status_color('done')
=> 'green'

A bit cleaner and less duplication, right?

However, in some cases you can just define a hash and get a value from a hash:

3. 2021: hash[key] => value # 

# app/models/task.rb
class Task < ApplicationRecord
  COLOR_STATUSES = { incoming: 'grey', todo: 'orange', done: 'green', spam: 'red', error: 'red' }.freeze
end

Task::COLOR_STATUSES['todo'] || 'black'
=> 'orange'
# Task::COLOR_STATUSES[@task.status.to_sym] || 'black'

In some cases this is better and simpler!

Here’s a real-world scenario where this approach is better (kudos @secretpray)