lodash/internal/cacheHas.js

define(['./isKeyable'], function(isKeyable) {

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

  /**
   * Checks if `value` is in `cache`.
   *
   * @private
   * @param {Object} cache The set cache to search.
   * @param {*} value The value to search for.
   * @returns {number} Returns `true` if `value` is found, else `false`.
   */
  function cacheHas(cache, value) {
    var map = cache.__data__;
    if (isKeyable(value)) {
      var data = map.__data__,
          hash = typeof value == 'string' ? data.string : data.hash;

      return hash[value] === HASH_UNDEFINED;
    }
    return map.has(value);
  }

  return cacheHas;
});