const obs = new MutationObserver((records) => {
    console.log(...records)
})

const s = new Set(['foo', 'bar'])

obs.observe(document.body, {
  attributeFilter: s.keys() // <--------- HERE
})

document.body.setAttribute('foo', 'foo')
document.body.removeAttribute('foo')
document.body.setAttribute('bar', 'bar')
document.body.removeAttribute('bar')