A method that calculates win streaks

Question

Right now, I have the following:

• A win_streak column on the User table.
• This method in game.rb

I'm interpreting win_streak as follows:

• The number if the number games in the streak
• The value (positive or negative) specifies whether those games were wins (positive) or losses (negative)

game.rb:

def adjust_streak
  u = self.user
  case self.result
    when 'Win'
      u.win_streak > 0 ? u.win_streak += 1 : u.win_streak = 1
    when 'Loss'
      u.win_streak > 0 ? u.win_streak = -1 : u.win_streak -= 1
    end
  u.save
end

I'm looking for a cleaner, and more succinct way to do this (e.g. keep track of win/loss streaks).

Answer 1

• You can use Array#min and Array#max to calculate the win/lose streak;
• You don't need to use self on getters;
• And you can use user.update instead of assigning and calling .save;
• I would also rename the win_streak column to streak;

---

def adjust_streak
  streak = case result
           when 'Win'  then [user.streak, 0].max + 1
           when 'Loss' then [user.streak, 0].min - 1
           end

  user.update streak: streak
end

Answer 2

Can the result be a tie? If not, then you can store wins and losses as Boolean values.

Thus you can use reduce the method to:

def adjust_streak
  u = self.user
  self.result == 1 ? u.win_streak += 1 : u.win_streak = 0
  u.save
end

If the result is a 'Win' (1/true) then increment the win streak, otherwise if the result is a loss the win streak is 0.

The value (positive or negative) specifies whether those games were wins (positive) or losses (negative)

This can be the sum of the result column if you are saving the values as 1 and 0.

Answer 3

I played around with a bunch of options, but kept coming back to the structure you have. So here are a couple tweaks you could apply:

Make the logic in the cases look more alike / easier to reason about:

def adjust_streak
  u = self.user
  case self.result
    when 'Win'
      u.win_streak > 0 ? u.win_streak += 1 : u.win_streak = 1
    when 'Loss'
      u.win_streak < 0 ? u.win_streak -= 1 : u.win_streak = -1
    end
  u.save
end

Could use #positive?/#negative?:

def adjust_streak
  u = self.user
  case self.result
    when 'Win'
      u.win_streak.positive? ? u.win_streak += 1 : u.win_streak = 1
    when 'Loss'
      u.win_streak.negative? ? u.win_streak -= 1 : u.win_streak = -1
    end
  u.save
end

DRY up assignment (assumes result can only be "Win" or "Loss"):

def adjust_streak
  u = self.user
  u.win_streak = case self.result
    when 'Win'
      u.win_streak.positive? ? u.win_streak + 1 : 1
    when 'Loss'
      u.win_streak.negative? ? u.win_streak - 1 : -1
    end
  u.save
end

As you mentioned in the comment on the other answer, the column name should be streak instead of win_streak.