Combine unless operator

app/controllers/password_resets_controller.rb

 class PasswordResetsController < ApplicationController
   before_action :get_user,   only: [:edit, :update]
   before_action :valid_user, only: [:edit, :update]
-  before_action :check_expiration, only: [:edit, :update]    # Case (1)
+  before_action :check_expiration, only: [:edit, :update]
 
   def create
     @user = User.find_by(email: params[:password_reset][:email].downcase)
@@ -20,16 +20,16 @@ class PasswordResetsController < ApplicationController
   end
 
   def update
-    if params[:user][:password].empty?                  # Case (3)
+    if params[:user][:password].empty?
       @user.errors.add(:password, "can't be empty")
       render "edit"
-    elsif @user.update_attributes(user_params)          # Case (4)
+    elsif @user.update_attributes(user_params)
       log_in @user
       @user.update_attribute(:reset_digest, nil)
       flash[:success] = "Password has been reset."
       redirect_to @user
     else
-      render "edit"                                     # Case (2)
+      render "edit"
     end
   end
 
@@ -45,9 +45,7 @@ class PasswordResetsController < ApplicationController
 
   # Confirms a valid user.
   def valid_user
-    unless (@user && @user.activated? && @user.authenticated?(:reset, params[:id]))
-      redirect_to root_url
-    end
+    return redirect_to root_url  unless (@user && @user.activated? && @user.authenticated?(:reset, params[:id]))
   end
 
   # Checks expiration of reset token.