2 var $ = require('../internals/export');
3 var IS_PURE = require('../internals/is-pure');
4 var getBuiltIn = require('../internals/get-built-in');
5 var anObject = require('../internals/an-object');
6 var aFunction = require('../internals/a-function');
7 var speciesConstructor = require('../internals/species-constructor');
8 var iterate = require('../internals/iterate');
10 // `Set.prototype.difference` method
11 // https://github.com/tc39/proposal-set-methods
12 $({ target: 'Set', proto: true, real: true, forced: IS_PURE }, {
13 difference: function difference(iterable) {
14 var set = anObject(this);
15 var newSet = new (speciesConstructor(set, getBuiltIn('Set')))(set);
16 var remover = aFunction(newSet['delete']);
17 iterate(iterable, function (value) {
18 remover.call(newSet, value);