lodash/lodash._setcache/index.js

/**
 * lodash 4.0.2 (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>
 */
var MapCache = require('lodash._mapcache');

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

/**
 *
 * Creates a set cache object to store unique values.
 *
 * @private
 * @constructor
 * @param {Array} [values] The values to cache.
 */
function SetCache(values) {
  var index = -1,
      length = values ? values.length : 0;

  this.__data__ = new MapCache;
  while (++index < length) {
    this.push(values[index]);
  }
}

/**
 * Adds `value` to the set cache.
 *
 * @private
 * @name push
 * @memberOf SetCache
 * @param {*} value The value to cache.
 */
function cachePush(value) {
  var map = this.__data__;
  if (isKeyable(value)) {
    var data = map.__data__,
        hash = typeof value == 'string' ? data.string : data.hash;

    hash[value] = HASH_UNDEFINED;
  }
  else {
    map.set(value, HASH_UNDEFINED);
  }
}

/**
 * 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;
}

// Add functions to the `SetCache`.
SetCache.prototype.push = cachePush;

module.exports = SetCache;