1  import { noop } from './utils.js';
 2  
 3  export const is_client = typeof window !== 'undefined';
 4  
 5  /** @type {() => number} */
 6  export let now = is_client ? () => window.performance.now() : () => Date.now();
 7  
 8  export let raf = is_client ? (cb) => requestAnimationFrame(cb) : noop;
 9  
10  // used internally for testing
11  /** @returns {void} */
12  export function set_now(fn) {
13  	now = fn;
14  }
15  
16  /** @returns {void} */
17  export function set_raf(fn) {
18  	raf = fn;
19  }