all these changes

frontend/node_modules/core-js/internals/to-set-like.js

@@ -0,0 +1,20 @@
+'use strict';
+var getBuiltIn = require('../internals/get-built-in');
+var isCallable = require('../internals/is-callable');
+var isIterable = require('../internals/is-iterable');
+var isObject = require('../internals/is-object');
+
+var Set = getBuiltIn('Set');
+
+var isSetLike = function (it) {
+  return isObject(it)
+    && typeof it.size == 'number'
+    && isCallable(it.has)
+    && isCallable(it.keys);
+};
+
+// fallback old -> new set methods proposal arguments
+module.exports = function (it) {
+  if (isSetLike(it)) return it;
+  return isIterable(it) ? new Set(it) : it;
+};