Finding multiple occurences of string and highlight them

fn.js

(find, content) => {
  // EXAMPLE
  // find = 'route found'
  // content = 'we found, that routes are commonly misinterpreted'
  // return:  'we <b>found</b>, that <b>route</b>s are commonly misinterpreted'
  var searchQueries = find.toLowerCase().split(' ')
  // highlight all parts of strings that were found
  for (var searchQuery in searchQueries) {
      searchQuery = searchQueries[searchQuery]
      if (!!~content.toLowerCase().indexOf(searchQuery)) {
          content = content.replace(
              // replace occurences only once
              new RegExp(`(${searchQuery})(?!\<\/b\>)`, 'i'),
              '<b>$1</b>'
          )
      }
  }
  return content
}