How to write fat arrow function.

fat.js

import io from 'socket.io-client'
const A = require('automerge')

const foo = bar => {
	bar.map( b => b.title )
}

startConnection() {
	this.socket = io('http://localhost:5000')

	this.socket.on('init', this.initConnection)

	this.socket.on('change', this.applyRemoteUpdates)
}

applyRemoteUpdates = ch => {

	if (ch.length == 0) return

	const changes = ch.filter(itm => itm.actor !== this.core.replica._actorId)

	if (changes.length == 0) {
		return
	}

	const newDoc = A.applyChanges(this.core.replica, changes)

	this.core.replica = newDoc
}