index.js

var { App } = require('choo')

var app = new App()
app.store(import('./stores/my-store'))
app.render('body')

my-store.js

var { Store } = require('choo')

export class myStore extends Store {
  static get name () {
    return 'my-store'
  }

  load () {
    this.emitter.on('foo', this.foo)
  }

  foo () {
    this.emitter.emit('log:info', 'hello world')
  }
}