TypeError: instance.createActivity is not a function

[joseito-terence]

Hey,

I'm getting the following error. I have no clue why.
Any input would be greatly appreciated.

(node:283) [MONGODB DRIVER] Warning: Top-level use of w, wtimeout, j, and fsync is deprecated. Use writeConcern instead.
events.js:377
      throw er; // Unhandled 'error' event
      ^
TypeError: instance.createActivity is not a function
    at FeedManager.activityCreated (/app/node_modules/getstream-node/src/FeedManager.js:78:28)
    at /app/node_modules/getstream-node/src/backends/mongoose.js:106:24
    at /app/node_modules/mongoose/lib/model.js:5074:18
    at processTicksAndRejections (internal/process/task_queues.js:77:11)
Emitted 'error' event on Function instance at:
    at /app/node_modules/mongoose/lib/model.js:5076:15
    at processTicksAndRejections (internal/process/task_queues.js:77:11)

Follow are my model and app.js files

/* model.js */
import mongoose, { Schema } from 'mongoose'
import stream from 'getstream-node'

var FeedManager = stream.FeedManager;

const favouriteSchema = new Schema({
  user: {
    type: Schema.ObjectId,
    ref: 'User',
    required: true
  },
  product: {
    type: Schema.ObjectId,
    ref: 'Product',
    required: true
  }
}, {
  timestamps: true,
  toJSON: {
    virtuals: true,
    transform: (obj, ret) => { delete ret._id }
  }
})

favouriteSchema.plugin(stream.mongoose.activity)

const model = mongoose.model('Favourite', favouriteSchema)

export const schema = model.schema
export default model

/* app.js */
import http from 'http'
import { env, mongo, port, ip, apiRoot } from './config'
import mongoose from './services/mongoose'
import express from './services/express'
import api from './api'
import stream from 'getstream-node'

const app = express(apiRoot, api)
const server = http.createServer(app)

if (mongo.uri) {
  mongoose.connect(mongo.uri)
}
mongoose.Promise = Promise



setImmediate(() => {
  server.listen(port, ip, () => {
    console.log('Express server listening on http://%s:%d, in %s mode', ip, port, env)
  })
});

stream.mongoose.setupMongoose(mongoose);

export default app