react-bootstrap/amd/lib/utils/createChainedFunction.js

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define(['exports', 'module'], function (exports, module) {
  /**
   * Safe chained function
   *
   * Will only create a new function if needed,
   * otherwise will pass back existing functions or null.
   *
   * @param {function} one
   * @param {function} two
   * @returns {function|null}
   */
  'use strict';

  function createChainedFunction(one, two) {
    var hasOne = typeof one === 'function';
    var hasTwo = typeof two === 'function';

    if (!hasOne && !hasTwo) {
      return null;
    }
    if (!hasOne) {
      return two;
    }
    if (!hasTwo) {
      return one;
    }

    return function chainedFunction() {
      one.apply(this, arguments);
      two.apply(this, arguments);
    };
  }

  module.exports = createChainedFunction;
});