lodash/_hashSet.js

define(['./_nativeCreate'], function(nativeCreate) {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /** Used to stand-in for `undefined` hash values. */
  var HASH_UNDEFINED = '__lodash_hash_undefined__';

  /**
   * Sets the hash `key` to `value`.
   *
   * @private
   * @name set
   * @memberOf Hash
   * @param {string} key The key of the value to set.
   * @param {*} value The value to set.
   * @returns {Object} Returns the hash instance.
   */
  function hashSet(key, value) {
    var data = this.__data__;
    data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
    return this;
  }

  return hashSet;
});