I'm lazy to use graph api and I just wanted to know what do people comment on FB, so here it is.

fb_helper.js

const getCommentsWithTime = () => [...document.querySelectorAll('.UFIComment')].map(comment => {
  const body = comment.querySelector('.UFICommentActorAndBody')

  if (body) {
    return {
      user: body.querySelector('.UFICommentActorName').innerText,
      text: body.querySelector('span:nth-child(2)').innerText,
      timestamp: comment.querySelector('.livetimestamp').innerText
    }
  }
}).filter(item => item)

const getUsers = comments => comments.map(x => x.user).filter((v, i, a) => a.indexOf(v) === i)

const getUsersComments = comments => getUsers(comments).map(user => ({
  user, comments: comments.filter(x => x.user === user).map(x => x.text)
}))


function matchKeywordFromComment(keyword) {
  const comments = getCommentsWithTime()
  const uca = getUsersComments(comments)

  return uca
    .map(x => ({
      user: x.user,
      match: x.comments.filter(x => x.indexOf(keyword) > -1)
    }))
    .filter(x => x.match.length > 0)
    .reduce((prev, cur) => [...prev, {[cur.user]: cur.match}], [])
    .reduce((prev, cur) => ({...prev, ...cur}))
}