wp-calypso/client/dashboard/app/queries/site-uptime.ts

import { fetchSiteUptime, type SiteUptime } from '../../data/site-jetpack-monitor-uptime';

export const siteUptimeQuery = ( siteId: number, period?: string ) => ( {
	queryKey: [ 'site', siteId, 'uptime', period ],
	queryFn: () => fetchSiteUptime( siteId, period ),
	select: ( uptime: Record< string, SiteUptime > ) => {
		// Post-process the data to calculate total number for up and down days during the time period.
		const { upDays, downDays } = Object.values( uptime ).reduce(
			( accumulator, { status } ) => {
				if ( status === 'monitor_inactive' ) {
					return accumulator;
				}

				accumulator[ status === 'up' ? 'upDays' : 'downDays' ] += 1;
				return accumulator;
			},
			{ upDays: 0, downDays: 0 }
		);

		if ( ! upDays && ! downDays ) {
			return undefined;
		}

		// Calculate the uptime percentage.
		return Math.round( ( upDays / ( upDays + downDays ) ) * 1000 ) / 10;
	},
} );