@zippytech/drag-helper/utils/once.js

A drag & drop utility

/**
 * Copyright 2015-present Zippy Technologies
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at

 *   http://www.apache.org/licenses/LICENSE-2.0

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use once';

module.exports = function once(fn, scope) {
  var called;
  var result;

  return function() {
    if (called) {
      return result;
    }

    called = true;

    return result = fn.apply(scope || this, arguments);
  };
};