/*
 * Copyright 2020 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {Metric} from '../types.js';

export const finalMetrics: WeakSet<Metric>|Set<Metric> = 'WeakSet' in window
  ? new WeakSet()
  : new Set();

/*
 * Copyright 2020 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {Metric} from '../types.js';


export const finalMetrics: WeakSet<Metric> = new WeakSet();

--- 
+++ 
@@ -16,5 +16,6 @@
 
 import {Metric} from '../types.js';
 
-
-export const finalMetrics: WeakSet<Metric> = new WeakSet();
+export const finalMetrics: WeakSet<Metric>|Set<Metric> = 'WeakSet' in window
+  ? new WeakSet()
+  : new Set();
Add support for Set in place of WeakSet
