Heap Overflow

Overview

Q&A community for developers, inspired by Stack Overflow.

Live Site

Features

• Q&A - Use rich text editing to ask or answer coding questions in a community of users
• Comments - Use markdown to discuss existing questions or answers and keep posts relevant and accurate
• Vote - Up vote helpful questions, answers, and comments written by other users. Downvote questions and answers that need improvement
• Search - Filter questions by tags or title
• Reputation - Receive/lose reputation in the community when other users upvote/downvote your post
• Badges - Receive badges for milestones, such as asking your first question or having a popular post

Technologies

• This project was built using React, Redux, and Ruby on Rails on top of a Postgresql database.

Code highlights

Users can vote on questions, answers, and comments. This feature is implemented using a polymorphic association built off votable_type and votable_id columns in the votes database table. The association is kept DRY using concerns, simplifying the addition of features with complex interactions such as reputation and badges:

module Votable
  extend ActiveSupport::Concern

  included do
    has_many :votes, as: :votable, dependent: :destroy
    has_many :voters, through: :votes
  end

  def addVote(vote)
    case vote.vote_type
      when "up_vote"
        self.update(score: self.score + 1)
        self.author.improveReputation(10)
      when "down_vote"
        self.update(score: self.score - 1)
        self.author.loseReputation(10)
      else
        return
      end
  end

  def undoVote(vote)
    case vote.vote_type
      when "up_vote"
        self.update(score: self.score - 1)
        self.author.loseReputation(10)
      when "down_vote"
        self.update(score: self.score + 1)
        self.author.improveReputation(10)
      else
        return      
      end
  end

  def award_popular_post_badge
    badge_name = "Popular Post"
    if self.score == 2 && !Badge.find_by(user_id: self.author.id, name: badge_name)
      Badge.create!(user_id: self.author.id, badge_type: 1, name: badge_name);
    end
  end

end

Libraries

This app uses the following open source libraries:

• React-Quill for rich-text question and answer forms
• react-markdown for rendering comments as markdown
• Moment to display elapsed time, e.g. "Asked 47 minutes ago"

License

MIT