add some packages

node_modules/core-js/library/modules/es6.set.js

@@ -0,0 +1,14 @@
+'use strict';
+var strong = require('./_collection-strong');
+var validate = require('./_validate-collection');
+var SET = 'Set';
+
+// 23.2 Set Objects
+module.exports = require('./_collection')(SET, function (get) {
+  return function Set() { return get(this, arguments.length > 0 ? arguments[0] : undefined); };
+}, {
+  // 23.2.3.1 Set.prototype.add(value)
+  add: function add(value) {
+    return strong.def(validate(this, SET), value = value === 0 ? 0 : value, value);
+  }
+}, strong);