createCache.js

var SetCache = require('./SetCache'),
    constant = require('../utility/constant'),
    isNative = require('../lang/isNative');

/** Native method references. */
var Set = isNative(Set = global.Set) && Set;

/* Native method references for those with the same name as other `lodash` methods. */
var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;

/**
 * Creates a `Set` cache object to optimize linear searches of large arrays.
 *
 * @private
 * @param {Array} [values] The values to cache.
 * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
 */
var createCache = !(nativeCreate && Set) ? constant(null) : function(values) {
  return new SetCache(values);
};

module.exports = createCache;