text: 
  const fs = require('fs')
  const path = require('path')
  
  class CSSAnimationKeys {
    constructor () {
      this.keys = this.__get()
    }
    get animated () { return this.keys.animated }
    get exempt () { return this.keys.exempt }
    get files () { return this.keys.files }
    __get () {
      return JSON.parse(fs.readFileSync(path.join(__dirname, 'keys.json'), 'utf8'))
    }
    __set () {
      let json = JSON.stringify(this.keys)
      fs.writeFileSync(path.join(__dirname, 'keys.json'), json, 'utf8')
      return this
    }
    add (key, value) {
      var changed = false
      if (typeof key === 'string' && this.keys[key] && typeof value !== 'undefined') {
        if (Array.isArray(value)) {
          value.forEach((val) => {
            if (addValue(val, this.keys[key])) {
              this.keys[key].push(value)
              changed = true
            }
          })
        } else if (addValue(value, this.keys[key])) {
          this.keys[key].push(value)
          changed = true
        }
      }
      if (changed) {
        return this.__set()
      }
      return this
    }
    join (data) {
      if (typeof data === 'object' && data !== null && data instanceof Object) {
        Object.assign(this.keys, data)
      }
      return this
    }
  }
  
  module.exports = new CSSAnimationKeys()
  
  function addValue (val, v) {
    if (typeof val === 'string' && val.length && !v.includes(val)) {
      return true
    }
    return false
  }
  