GET_LCP_PRIORITY function

The httparchive.fn.GET_LCP_PRIORITY function returns the value of the fetchpriority attribute of the LCP element.

Input

performance_custom_metric

The JSON-encoded performance custom metric of a page.

Type: STRING

Output

The value of the fetchpriority attribute of the LCP element, or null if the LCP element does not have a fetchpriority attribute.

Type: STRING

Example usage

Top fetchpriority values

WITH lcp AS (
  SELECT
    `httparchive.fn.GET_LCP_PRIORITY`(JSON_QUERY(custom_metrics, '$.performance')) AS priority
  FROM
    `httparchive.all.pages`
  WHERE
    date = '2023-11-01' AND
    client = 'mobile' AND
    is_root_page
)

SELECT
  APPROX_TOP_COUNT(priority, 10) AS priority
FROM
  lcp

Routine

try {
  const perf = JSON.parse(performance_custom_metric);
  const lcpAttrs = perf.lcp_elem_stats.attributes;
  return lcpAttrs.find(attr => attr.name == 'fetchpriority')?.value
} catch {
  return null;
}