talk/routes/api/stream/index.js

const express = require('express');

const Comment = require('../../../models/comment');
const User = require('../../../models/user');
const Action = require('../../../models/action');

const router = express.Router();

router.get('/', (req, res, next) => {
  const comments = Comment.findByAssetId(req.query.asset_id) || [];
  const users = User.findByIdArray(comments.map((comment) => comment.author_id));
  const actions = Action.findByItemIdArray(comments.map((comment) => comment.id));

  res.json(comments.concat(users).concat(actions)).catch(next);
});

module.exports = router;