https://blog.battlefy.com/how-not-to-blow-up-the-production-database-424c162dccc6 attempt #1

apex-legends-score-report.js

type ApexLegendsGameResult = {
  teamID: string,
  placement: number,
  kills: number
};

application.post('/apex-legends/:gameID/report-score', async ({params: {gameID}, body}, res) => {
  await db.collection('apexLegendsGames').updateOne({
    _id: gameID
  }, {
    $set: {
      state: 'completed',
      results: body as ApexLegendsGameResult[]
    }
  });
  
  return res.sendStatus(204);
});

tournaments-team-stats.js

application.get('/tournament/:tournamentID/team-stats', ({params: {tournamentID}, query: {sort, page}}, res) => {
  const games = await db.collection('apexLegendsGames').find({
    state: 'completed',
    tournamentID
  })
    .toArray();
  let totalKillsByTeamID = 0;
  for (const {results} of games) {
    for (const {teamID, kills} of results) {
      totalKillsByTeamID[teamID] = totalKillsByTeamID[teamID] || {};
      totalKillsByTeamID[teamID] += kills;
    }
  }
  
  const teamIDs = Object.keys(totalKillsByTeamID);
  const teams = await db.collection('teams').find({
    _id: {
      $in: teamIDs
    }
  })
    .toArray();
  const teamByID = _.keyBy(teams, '_id');
  
  let teamsTable = teamIDs.map((teamID) => ({
    teamName: teamByID[teamID].name,
    totalKills: totalKillsByTeamID[teamID],
    averageKills: totalKillsByTeamID[teamID] / games.length
  }));
  teamsTable = _.sortBy(teamsTable, [sort]);
  const teamsPerPage = 10;
  const pageIndex = page * teamsPerPage;
  const page = teamsTable.slice(pageIndex, pageIndex + itemsPerPage);
  
  return res.send(page);
});