SwitchHosts/app-ui/content/cm_hl.js

// custom mode

'use strict'

import CodeMirror from 'codemirror'

export default function () {

  CodeMirror.defineMode('hosts', function () {
    function tokenBase (stream) {
      if (stream.eatSpace()) return null

      let sol = stream.sol()
      let ch = stream.next()

      let s = stream.string

      if (ch === '#') {
        stream.skipToEnd()
        return 'comment'
      }
      if (!s.match(/^\s*([\d.]+|[\da-f:.%lo]+)\s+\w/i)) {
        return 'error'
      }

      if (sol && ch.match(/[\w.:%]/)) {
        stream.eatWhile(/[\w.:%]/)
        return 'ip'
      }

      return null
    }

    function tokenize (stream, state) {
      return (state.tokens[0] || tokenBase)(stream, state)
    }

    return {
      startState: function () {
        return {tokens: []}
      },
      token: function (stream, state) {
        return tokenize(stream, state)
      },
      lineComment: '#'
    }
  })

  //CodeMirror.defineMIME('text/x-hosts', 'hosts');
}