cwv.js

let po = new PerformanceObserver((list) => {
    for (const entry of list.getEntries()) {
      console.log(entry);
    }
  });

  po.observe({type: 'layout-shift', buffered: true});

let po2 = new PerformanceObserver((list) => {
    for (const entry of list.getEntries()) {
      console.log(entry);
    }
  });

  po2.observe({ type: 'largest-contentful-paint', buffered: true});