mock.js

const request = require('superagent'); // you know…
const mock = require('superagent-crud-mock'); // my awesome mock module
const topics = require('./topics'); // service provider, for example it's localstorage

mock(superagent) // patch `superagent`
  .get('/topics/', (req, res) => {
    res.json(topics.get()); // send json with data taken from the service
  })
  .get('/topics/:id', (req, res) => {
    res.json(topics.get(req.params.id));
  })
  .post('/topics/:id', (req, res) => {
    res.json(topics.create(data));
  })
  .put('/topics/:id', (req, res) => {
    res.json(topics.update(ctx.data));
  })
  .del('topics/:id',  (req, res) => {
    res.json(topics.del(ctx.data))
  })
;