--- /dev/null
+'use strict';
+var anObject = require('../internals/an-object');
+var aFunction = require('../internals/a-function');
+
+// https://github.com/tc39/collection-methods
+module.exports = function (/* ...elements */) {
+ var set = anObject(this);
+ var adder = aFunction(set.add);
+ for (var k = 0, len = arguments.length; k < len; k++) {
+ adder.call(set, arguments[k]);
+ }
+ return set;
+};