lodash/lodash._cachehas/index.js

/**
 * lodash 4.0.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */

/** 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);
}

/**
 * Checks if `value` is suitable for use as unique object key.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
 */
function isKeyable(value) {
  var type = typeof value;
  return type == 'number' || type == 'boolean' ||
    (type == 'string' && value !== '__proto__') || value == null;
}

module.exports = cacheHas;