1
2
3
4
5
6
7
8
9
10
11
12
13
14
  | import { TimestampProvider } from '../types'; 
 |    
 |  interface PerformanceTimestampProvider extends TimestampProvider { 
 |    delegate: TimestampProvider | undefined; 
 |  } 
 |    
 |  export const performanceTimestampProvider: PerformanceTimestampProvider = { 
 |    now() { 
 |      // Use the variable rather than `this` so that the function can be called 
 |      // without being bound to the provider. 
 |      return (performanceTimestampProvider.delegate || performance).now(); 
 |    }, 
 |    delegate: undefined, 
 |  }; 
 |  
  |