listen cheat code on web page

CheatCodeRegister.js

/**
 * @namespace registerCheatCode
 */

/**
 * @typedef {object} registerCheatCode~api
 * @property {registerCheatCode~api~on} on
 * @property {registerCheatCode~api~remove} remove
 * @property {registerCheatCode~api~register} register
 */

/**
 * @callback registerCheatCode~api~on
 * @param {EventListener} listener
 * @return {registerCheatCode~api}
 */

/**
 * @callback registerCheatCode~api~remove
 * @return {registerCheatCode~api}
 */

/**
 * @callback registerCheatCode~api~register
 * @return {registerCheatCode~api}
 */

/**
 * @function registerCheatCode
 * @param {string} name - cheat code name
 * @param {string[]} sequence - cheat code sequence
 * @return {{on: function(function), listener: function}} minimal object for listen cheatcode finish
 * @example
 * registerCheatCode('konami_code', [
 *  'ArrowUp', 'ArrowUp',
 *  'ArrowDown', 'ArrowDown',
 *  'ArrowLeft', 'ArrowRight',
 *  'ArrowLeft', 'ArrowRight',
 *  'b', 'a',
 * ]).on(evt => alert('Great! Your good enougth for enter konami code.'))
 */
function registerCheatCode(name, sequence) {
  let progress = 0;

  const listener = ({key}) => {
    if (sequence[progress] === key) {
      if (++progress < sequence.length) return

      window.dispatchEvent(new CustomEvent(name, {detail: listener}))
    }

    progress = 0
  }

  const onListeners = []
  const api = {
    on(cheatListener) {
      onListeners.push(cheatListener)
      window.addEventListener(name, cheatListener)

      return api
    },
    remove() {
      window.removeEventListener('keyup', listener)

      let cl;
      while (cl = onListeners.pop()) {
        window.removeEventListener(name, cl)
      }

      return api
    },
    register() {
      progress = 0
      window.addEventListener('keyup', listener)

      return api
    }
  }

  return api.register()
}