All files / core/stats StatsListener.ts

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
12x
 
 
 
 
 
 
 
 
12x
15x
 
15x
 
12x
10x
 
10x
10x
 
 
 
 
10x
 
10x
 
12x
 
/**
 * Copyright 2017 Google Inc.
 *
 * 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
 *
 *   http://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 { clone, forEach } from '@firebase/util';
import { StatsCollection } from './StatsCollection';
 
/**
 * Returns the delta from the previous call to get stats.
 *
 * @param collection_ The collection to "listen" to.
 * @constructor
 */
export class StatsListener {
  private last_: { [k: string]: number } | null = null;
 
  constructor(private collection_: StatsCollection) {}
 
  get(): { [k: string]: number } {
    const newStats = this.collection_.get();
 
    const delta: typeof newStats = clone(newStats);
    Iif (this.last_) {
      forEach(this.last_, (stat: string, value: number) => {
        delta[stat] = delta[stat] - value;
      });
    }
    this.last_ = newStats;
 
    return delta;
  }
}