LargestContentfulPaint.size

The size read-only property of the LargestContentfulPaint interface returns the intrinsic size of the element that is the largest contentful paint.

The size of the element is the width times height of the rectangle that this element creates on the screen.

An integer representing the width times height of the element.

The following example gets the LargestContentfulPaint object and prints the value of size to the console.

try {
  let lcp;

  const po = new PerformanceObserver((entryList) => {
    const entries = entryList.getEntries();
    const lastEntry = entries[entries.length - 1];
    console.log(lastEntry.size);
  });

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

} catch (e) {
  // Do nothing if the browser doesn't support this API.
}