var on = require('on-off')
var off = on.off

on(document.body, 'click', hello) // adds the event listener
off(document.body, 'click', hello) // removes

on(document.body.children, 'click', hello) // add to array or NodeList of elements elements
on('a', 'click', hello) // add to multiple elements via selector
on('a', 'click touchstart', hello) // add multiple listeners at once

function hello () {
  console.log('hello!')
}