'use strict'; var $ = require('../internals/export'); var IS_PURE = require('../internals/is-pure'); var getBuiltIn = require('../internals/get-built-in'); var anObject = require('../internals/an-object'); var aFunction = require('../internals/a-function'); var speciesConstructor = require('../internals/species-constructor'); var iterate = require('../internals/iterate'); // `Set.prototype.intersection` method // https://github.com/tc39/proposal-set-methods $({ target: 'Set', proto: true, real: true, forced: IS_PURE }, { intersection: function intersection(iterable) { var set = anObject(this); var newSet = new (speciesConstructor(set, getBuiltIn('Set')))(); var hasCheck = aFunction(set.has); var adder = aFunction(newSet.add); iterate(iterable, function (value) { if (hasCheck.call(set, value)) adder.call(newSet, value); }); return newSet; } });