mongo_pagination.js

exports.getLists = async (query) => {
  const sort = { _id: -1 }
  // Max of 30 records
  query.limit = parseInt(query.limit || 10)
  const limit = query.limit > 30 ? 30 : query.limit

  let hasNext = false
  let hasPrev = false

  const q = {
    domain: query.domain,
    archived: { $exists: false }
  }
  if (query.previous_cursor) {
    q._id = { $gt: dbo.id(query.previous_cursor) }
    sort._id = 1
  } else if (query.next_cursor) {
    q._id = { $lt: dbo.id(query.next_cursor) }
  }

  const r = await dbo.db().collection('lists').find(q, {
    sort,
    limit
  }).toArray()

  if (query.previous_cursor) r.reverse()

  if (r.length) {
    q._id = {
      $lt: dbo.id(r[r.length - 1]._id)
    }
    hasNext = !!await dbo.db().collection('lists').findOne(q)
    q._id = {
      $gt: dbo.id(r[0]._id)
    }
    hasPrev = !!await dbo.db().collection('lists').findOne(q)
  }

  const o = {
    data: r.map(l => new ListResponse(l))
  }
  if (hasNext) {
    o.next_cursor = r[r.length - 1]._id + ''
  }
  if (hasPrev) {
    o.previous_cursor = r[0]._id + ''
  }

  return o
}

exports.avatar = (email, uid, s) => {
  const initials = email ? email[0] : 'oo'
  const backup = `https://tiley.herokuapp.com/avatar/${uid}/${initials}.png`
  // const backup = `https://avatar.tobi.sh/${uid}`
  if (!email) {
    return backup
  }
  email = email.trim().toLowerCase()
  if (!s) {
    s = 200
  }
  const hash = crypto.createHash('md5').update(email).digest('hex').toString()
  return `https://www.gravatar.com/avatar/${hash}?s=${s}&d=${encodeURIComponent(backup)}`
}