code: function hasInsertionPoint (file) {
    var token = appOptions.pageToken
  
    if (token !== '' && String(file.contents).indexOf(token) > -1) {
      insertionPoint = 'token'
      return true
    } else if (token !== '' && token !== defaults.pageToken) {
      logger('Token not found in ' + file.relative)
    }
  
    var soup = new Soup(String(file.contents))
  
    // Append after metas
    soup.setInnerHTML('head > meta:last-of-type', function (oldHTML) {
      if (oldHTML !== null) {
        insertionPoint = 'meta'
        return oldHTML
      }
    })
  
    if (insertionPoint) {
      return true
    }
  
    // Else, prepend before links
    soup.setInnerHTML('head > link:first-of-type', function (oldHTML) {
      if (oldHTML !== null) {
        insertionPoint = 'link'
        return oldHTML
      }
    })
  
    if (insertionPoint) {
      return true
    }
  
    // Else, append to head
    soup.setInnerHTML('head', function (oldHTML) {
      if (oldHTML !== null) {
        insertionPoint = 'head'
        return oldHTML
      }
    })
  
    return insertionPoint
  }
docs: Determine if file has a valid area to inject resource hints
  @param {stream} file