Community Features

Overview

SkillRise’s community platform enables peer-to-peer learning through groups, posts, and replies. Students can ask questions, share knowledge, and build connections with fellow learners.

Community Architecture

Data Models

Group Schema

server/models/Group.js

import mongoose from 'mongoose'

const groupSchema = new mongoose.Schema(
  {
    name: { type: String, required: true },
    slug: { 
      type: String, 
      required: true, 
      unique: true, 
      lowercase: true 
    },
    description: { type: String, default: '' },
    icon: { type: String, default: '💬' },
    memberCount: { type: Number, default: 0 },
    postCount: { type: Number, default: 0 },
    createdBy: { type: String, default: 'system' },
    isOfficial: { type: Boolean, default: false },
  },
  { timestamps: true }
)

const Group = mongoose.model('CommunityGroup', groupSchema)
export default Group

Groups use URL-friendly slugs generated from names, with automatic uniqueness checking.

Community Post Schema

server/models/CommunityPost.js

import mongoose from 'mongoose'

const communityPostSchema = new mongoose.Schema(
  {
    authorId: { type: String, required: true },
    authorName: { type: String, required: true },
    authorImage: { type: String, default: '' },
    groupId: { 
      type: mongoose.Schema.Types.ObjectId, 
      ref: 'CommunityGroup', 
      default: null 
    },
    title: { type: String, required: true },
    content: { type: String, required: true },
    tags: [{ type: String }],
    upvotes: [{ type: String }], // array of userIds
    replyCount: { type: Number, default: 0 },
    isResolved: { type: Boolean, default: false },
  },
  { timestamps: true }
)

communityPostSchema.index({ groupId: 1, createdAt: -1 })
communityPostSchema.index({ createdAt: -1 })

const CommunityPost = mongoose.model('CommunityPost', communityPostSchema)
export default CommunityPost

Reply Schema

server/models/Reply.js

import mongoose from 'mongoose'

const replySchema = new mongoose.Schema(
  {
    postId: {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'CommunityPost',
      required: true,
      index: true,
    },
    authorId: { type: String, required: true },
    authorName: { type: String, required: true },
    authorImage: { type: String, default: '' },
    content: { type: String, required: true },
    upvotes: [{ type: String }],
    isAcceptedAnswer: { type: Boolean, default: false },
  },
  { timestamps: true }
)

const Reply = mongoose.model('CommunityReply', replySchema)
export default Reply

Upvotes are stored as arrays of user IDs, allowing efficient membership checks and preventing duplicate votes.

Group Management

List All Groups

server/controllers/communityController.js

export const getGroups = async (req, res) => {
  try {
    const userId = req.auth?.userId
    const groups = await Group.find()
      .sort({ isOfficial: -1, memberCount: -1 })
      .lean()

    let memberSet = new Set()
    if (userId) {
      const memberships = await GroupMembership.find({ userId })
        .select('groupId')
        .lean()
      memberSet = new Set(memberships.map((m) => m.groupId.toString()))
    }

    const result = groups.map(({ createdBy, ...g }) => ({
      ...g,
      isMember: memberSet.has(g._id.toString()),
    }))
    
    res.json({ success: true, groups: result })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Fetch Groups

Retrieve all groups, sorting official groups first, then by member count.

Check Memberships

Query memberships for the authenticated user to determine joined status.

Enrich Response

Add isMember flag to each group for UI rendering.

Create Group

server/controllers/communityController.js

export const createGroup = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const { name, description, icon } = req.body
    if (!name?.trim()) {
      return res.json({ 
        success: false, 
        message: 'Group name is required' 
      })
    }

    // Generate slug from name
    const slug = name
      .trim()
      .toLowerCase()
      .replace(/[^a-z0-9]+/g, '-')
      .replace(/^-|-$/g, '')
      
    // Check for existing group with same slug or name
    const existing = await Group.findOne({
      $or: [
        { slug },
        {
          name: {
            $regex: new RegExp(
              `^${name.trim().replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}$`, 
              'i'
            ),
          },
        },
      ],
    })
    
    if (existing) {
      return res.json({ 
        success: false, 
        message: 'A group with this name already exists' 
      })
    }

    const group = await Group.create({
      name: name.trim().slice(0, 60),
      slug,
      description: (description || '').trim().slice(0, 200),
      icon: icon || '💬',
      createdBy: userId,
    })
    
    // Auto-join creator
    await GroupMembership.create({ userId, groupId: group._id })
    const updated = await Group.findByIdAndUpdate(
      group._id,
      { $inc: { memberCount: 1 } },
      { new: true }
    ).lean()

    const { createdBy, ...groupData } = updated
    res.json({ 
      success: true, 
      group: { ...groupData, isMember: true } 
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Group names are validated for uniqueness (case-insensitive) and slugs are automatically generated to prevent URL conflicts.

Toggle Membership

server/controllers/communityController.js

export const toggleMembership = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const { groupId } = req.params
    const existing = await GroupMembership.findOne({ userId, groupId })

    if (existing) {
      // Leave group
      await GroupMembership.deleteOne({ userId, groupId })
      await Group.findByIdAndUpdate(groupId, { $inc: { memberCount: -1 } })
      res.json({ success: true, isMember: false })
    } else {
      // Join group
      await GroupMembership.create({ userId, groupId })
      await Group.findByIdAndUpdate(groupId, { $inc: { memberCount: 1 } })
      res.json({ success: true, isMember: true })
    }
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Membership toggle is idempotent - calling it multiple times won’t create duplicate memberships or incorrect counts.

Post Management

Create Post

server/controllers/communityController.js

export const createPost = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const { title, content, groupId, tags } = req.body
    if (!title?.trim() || !content?.trim()) {
      return res.json({ 
        success: false, 
        message: 'Title and content are required' 
      })
    }

    const author = await User.findById(userId)
    if (!author) {
      return res.json({ 
        success: false, 
        message: 'User not found' 
      })
    }

    // Parse tags from array or comma-separated string
    const parsedTags = Array.isArray(tags)
      ? tags.map((tag) => tag.trim()).filter(Boolean).slice(0, 5)
      : typeof tags === 'string'
        ? tags.split(',').map((tag) => tag.trim()).filter(Boolean).slice(0, 5)
        : []

    const post = await CommunityPost.create({
      authorId: userId,
      authorName: author.name,
      authorImage: author.imageUrl || '',
      groupId: groupId || null,
      title: title.trim().slice(0, 200),
      content: content.trim().slice(0, 5000),
      tags: parsedTags,
    })

    if (groupId) {
      await Group.findByIdAndUpdate(groupId, { $inc: { postCount: 1 } })
    }

    const populated = await CommunityPost.findById(post._id)
      .populate('groupId', 'name slug icon')
      .lean()
      
    res.json({
      success: true,
      post: enrichPost({ ...populated, group: populated.groupId }, userId),
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Posts can belong to a group or be posted globally (groupId: null). Tags are limited to 5 per post.

Get Posts with Filters

server/controllers/communityController.js

export const getPosts = async (req, res) => {
  try {
    const userId = req.auth?.userId
    const { groupId, tab = 'all', page = 1 } = req.query
    const LIMIT = 15
    const skip = (parseInt(page) - 1) * LIMIT

    // Build base query
    const query = {}
    if (groupId) {
      query.groupId = groupId
    } else if (tab === 'myGroups' && userId) {
      const memberships = await GroupMembership.find({ userId })
        .select('groupId')
        .lean()
      query.groupId = { $in: memberships.map((m) => m.groupId) }
    }

    let posts, total

    if (tab === 'trending') {
      // Sort by upvote count using aggregation
      const pipeline = [
        { $match: query },
        { $addFields: { upvoteCount: { $size: '$upvotes' } } },
        { $sort: { upvoteCount: -1, createdAt: -1 } },
        { $skip: skip },
        { $limit: LIMIT },
        {
          $lookup: {
            from: 'communitygroups',
            localField: 'groupId',
            foreignField: '_id',
            as: 'groupArr',
          },
        },
        { $addFields: { group: { $arrayElemAt: ['$groupArr', 0] } } },
        { $project: { groupArr: 0 } },
      ]
      posts = await CommunityPost.aggregate(pipeline)
      total = await CommunityPost.countDocuments(query)
    } else {
      // Default sort by most recent
      const raw = await CommunityPost.find(query)
        .sort({ createdAt: -1 })
        .skip(skip)
        .limit(LIMIT)
        .populate('groupId', 'name slug icon')
        .lean()
      posts = raw.map((p) => ({ ...p, group: p.groupId, groupId: undefined }))
      total = await CommunityPost.countDocuments(query)
    }

    const enriched = posts.map((p) => enrichPost(p, userId))
    res.json({ 
      success: true, 
      posts: enriched, 
      hasMore: skip + posts.length < total, 
      total 
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Build Query

Filter by group, my groups, or all posts based on tab selection.

Sort Strategy

Use aggregation for trending (upvote count) or simple sort for recent posts.

Pagination

Implement limit/skip pagination with hasMore flag for infinite scroll.

Enrich Data

Add user-specific flags (isAuthor, isUpvoted) and hide sensitive data.

Post Enrichment Helper

server/controllers/communityController.js

const enrichPost = (post, userId) => ({
  ...post,
  authorId: undefined,
  isAuthor: userId ? post.authorId === userId : false,
  group: post.groupId ?? post.group ?? null,
  groupId: undefined,
  upvoteCount: Array.isArray(post.upvotes) ? post.upvotes.length : 0,
  isUpvoted: userId 
    ? Array.isArray(post.upvotes) && post.upvotes.includes(userId) 
    : false,
  upvotes: undefined,
})

The enrichment helper strips the upvotes array and authorId for privacy while adding computed flags for UI rendering.

Reply System

Create Reply

server/controllers/communityController.js

export const createReply = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const { content } = req.body
    if (!content?.trim()) {
      return res.json({ 
        success: false, 
        message: 'Reply content is required' 
      })
    }

    const post = await CommunityPost.findById(req.params.postId)
    if (!post) {
      return res.json({ 
        success: false, 
        message: 'Post not found' 
      })
    }

    const author = await User.findById(userId)
    if (!author) {
      return res.json({ 
        success: false, 
        message: 'User not found' 
      })
    }

    const reply = await Reply.create({
      postId: post._id,
      authorId: userId,
      authorName: author.name,
      authorImage: author.imageUrl || '',
      content: content.trim().slice(0, 3000),
    })

    post.replyCount += 1
    await post.save()

    res.json({
      success: true,
      reply: {
        ...reply.toObject(),
        authorId: undefined,
        isAuthor: true,
        upvoteCount: 0,
        isUpvoted: false,
        upvotes: undefined,
      },
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Get Post with Replies

server/controllers/communityController.js

export const getPost = async (req, res) => {
  try {
    const userId = req.auth?.userId
    const post = await CommunityPost.findById(req.params.postId)
      .populate('groupId', 'name slug icon')
      .lean()
      
    if (!post) {
      return res.json({ 
        success: false, 
        message: 'Post not found' 
      })
    }

    // Replies: accepted answer first, then by creation time
    const rawReplies = await Reply.find({ postId: post._id })
      .sort({ isAcceptedAnswer: -1, createdAt: 1 })
      .lean()

    const replies = rawReplies.map((r) => ({
      ...r,
      authorId: undefined,
      isAuthor: userId ? r.authorId === userId : false,
      upvoteCount: r.upvotes.length,
      isUpvoted: userId ? r.upvotes.includes(userId) : false,
      upvotes: undefined,
    }))

    res.json({
      success: true,
      post: { 
        ...enrichPost({ ...post, group: post.groupId }, userId), 
        replies 
      },
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Accepted answers always appear first in the reply list, followed by chronological order.

Upvoting System

Toggle Post Upvote

server/controllers/communityController.js

export const togglePostUpvote = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const post = await CommunityPost.findById(req.params.postId)
    if (!post) {
      return res.json({ 
        success: false, 
        message: 'Post not found' 
      })
    }

    const idx = post.upvotes.indexOf(userId)
    idx > -1 
      ? post.upvotes.splice(idx, 1) 
      : post.upvotes.push(userId)
    await post.save()

    res.json({ 
      success: true, 
      upvoteCount: post.upvotes.length, 
      isUpvoted: idx === -1 
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Toggle Reply Upvote

server/controllers/communityController.js

export const toggleReplyUpvote = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const reply = await Reply.findById(req.params.replyId)
    if (!reply) {
      return res.json({ 
        success: false, 
        message: 'Reply not found' 
      })
    }

    const idx = reply.upvotes.indexOf(userId)
    idx > -1 
      ? reply.upvotes.splice(idx, 1) 
      : reply.upvotes.push(userId)
    await reply.save()

    res.json({ 
      success: true, 
      upvoteCount: reply.upvotes.length, 
      isUpvoted: idx === -1 
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Upvote arrays naturally prevent duplicates - attempting to upvote twice will remove the vote instead.

Accepted Answers

Accept Answer (Post Author Only)

server/controllers/communityController.js

export const acceptAnswer = async (req, res) => {
  try {
    const userId = req.auth?.userId
    if (!userId) {
      return res.status(401).json({ 
        success: false, 
        message: 'Authentication required' 
      })
    }

    const post = await CommunityPost.findById(req.params.postId)
    if (!post) {
      return res.json({ 
        success: false, 
        message: 'Post not found' 
      })
    }
    
    if (post.authorId !== userId) {
      return res.status(403).json({ 
        success: false, 
        message: 'Only the post author can accept an answer' 
      })
    }

    const reply = await Reply.findById(req.params.replyId)
    if (!reply) {
      return res.json({ 
        success: false, 
        message: 'Reply not found' 
      })
    }

    // Unaccept all answers first (only one accepted answer per post)
    await Reply.updateMany(
      { postId: post._id }, 
      { isAcceptedAnswer: false }
    )

    const nowAccepted = !reply.isAcceptedAnswer
    if (nowAccepted) {
      await Reply.findByIdAndUpdate(reply._id, { isAcceptedAnswer: true })
      post.isResolved = true
      await post.save()
    }

    res.json({ 
      success: true, 
      isAcceptedAnswer: nowAccepted, 
      postResolved: post.isResolved 
    })
  } catch (error) {
    console.error(error)
    res.status(500).json({ 
      success: false, 
      message: 'An unexpected error occurred' 
    })
  }
}

Authorization Check

Verify the requester is the post author.

Clear Previous Answers

Unaccept all other answers for the post.

Mark Answer

Set the selected reply as the accepted answer.

Resolve Post

Mark the post as resolved when an answer is accepted.

Community Features

Groups

Topic-based communities with membership tracking and post counts.

Posts

Questions and discussions with tags, upvotes, and resolved status.

Replies

Threaded responses with accepted answer functionality.

Upvoting

Community-driven content ranking for posts and replies.

Resolution

Question resolution system with accepted answers.

Tabs and Filters

All Posts (Default)

Shows all posts across all groups, sorted by most recent.

My Groups

Only shows posts from groups the user has joined.

Group Filter

Filter posts to a specific group using the groupId query parameter.

Pagination

The community uses limit/skip pagination with 15 posts per page:

const LIMIT = 15
const skip = (parseInt(page) - 1) * LIMIT

Response includes hasMore flag for infinite scroll:

hasMore: skip + posts.length < total

Best Practices

Privacy Protection

Strip upvote arrays and author IDs from responses to protect user privacy.

Denormalized Counts

Store memberCount, postCount, and replyCount for efficient queries.

Composite Indexes

Use compound indexes on groupId + createdAt for optimal query performance.

Author-Only Actions

Verify ownership before allowing delete, edit, or accept answer operations.

Content Limits

Group names: 60 characters
Group descriptions: 200 characters
Post titles: 200 characters
Post content: 5,000 characters
Reply content: 3,000 characters
Tags per post: 5

Next Steps

Authentication

Understand user roles and access control

AI Features

Leverage AI for personalized learning assistance

Analytics

Track engagement and learning patterns

​Overview

​Community Architecture

​Data Models

​Group Schema

​Community Post Schema

​Reply Schema

​Group Management

​List All Groups

​Create Group

​Toggle Membership

​Post Management

​Create Post

​Get Posts with Filters

​Post Enrichment Helper

​Reply System

​Create Reply

​Get Post with Replies

​Upvoting System

​Toggle Post Upvote

​Toggle Reply Upvote

​Accepted Answers

​Accept Answer (Post Author Only)

​Community Features

Groups

Posts

Replies

Upvoting

Tags

Resolution

​Tabs and Filters

​Pagination

​Best Practices

Privacy Protection

Denormalized Counts

Composite Indexes

Author-Only Actions

​Content Limits

​Next Steps

Authentication

AI Features

Analytics

Overview

Community Architecture

Data Models

Group Schema

Community Post Schema

Reply Schema

Group Management

List All Groups

Create Group

Toggle Membership

Post Management

Create Post

Get Posts with Filters

Post Enrichment Helper

Reply System

Create Reply

Get Post with Replies

Upvoting System

Toggle Post Upvote

Toggle Reply Upvote

Accepted Answers

Accept Answer (Post Author Only)

Community Features

Tabs and Filters

Pagination

Best Practices

Content Limits

Next Steps