"use strict";
  
  Object.defineProperty(exports, "__esModule", {
      value: true
  });
  exports.default = once;
  function once(fn) {
      return function () {
          if (fn === null) return;
          var callFn = fn;
          fn = null;
          callFn.apply(this, arguments);
      };
  }
  module.exports = exports["default"];