performance-timing 
A straight-forward interface to retrieving performance timing metrics.
What does it do for me?
Retrieve metrics if they are available, otherwise, set up an observer to be resolved with extracted entries, then disconnected.
import { getEntries } from 'performance-timing';
const [ navigation ] = await getEntries('navigation'); // PerformanceNavigationTiming{}More Examples
const [ firstInpt ] = await getEntries('first-input'); // PerformanceEventTiming{}
const resources = await getEntries('resource'); // [PerformanceResourceTiming{}, ...]Mixed results
const entries = await getEntries('navigation', 'paint');