Human-readable (and reasonable) date-time interval format function in PHP.

format_reasonable_interval.php

	/**
	 * Human-readable and reasonable date-time interval formatter
	 * ----------------------------------------------------------
	 * Author: Benyamin shoham
	 * -----------------------
	 * Format an interval to show existing components in a Human Readable fashion
	 * If the interval doesn't have a time component (years, months, etc)
	 * That component won't be displayed.
	 * You can decide how many components will be displayed (e.g. "1 year 2 months" = 2 components)
	 * You can select a delimiter to format the interval (e.g. "1 year aaaand 2 months"
	 *
	 * Idea is based on source: https://gist.github.com/xadim/8cf3569ee14ec943c324
	 *
	 * @param DateInterval $interval - The interval
	 *
	 * @param int $max_parts - number of interval parts to return. Default = 2
	 *
	 * @param string $delimiter - Inserted after each part, except the last one. Default = ' ' (one space)
	 *
	 * @return string Formatted interval string.
	 */
	function format_reasonable_interval( DateInterval $interval, $max_parts = 2, $delimiter = ' ' ) {
		$result       = "";
		$parts        = 0;
		$interval_map = [
			'year'   => [ 'interval' => $interval->y, 'format' => '%y year' ],
			'month'  => [ 'interval' => $interval->m, 'format' => '%m month' ],
			'day'    => [ 'interval' => $interval->d, 'format' => '%d day' ],
			'hour'   => [ 'interval' => $interval->h, 'format' => '%h hour' ],
			'minute' => [ 'interval' => $interval->i, 'format' => '%i minute' ],
			'second' => [ 'interval' => $interval->s, 'format' => '%s second' ],
		];

		foreach ( $interval_map as $interval_part ) {
			if ( $interval_part['interval'] && $parts < $max_parts ) {

				// Format interval part using map.
				$result .= $interval->format( $interval_part['format'] );

				// Add plural suffix if interval part is larger than 1
				// e.g. 1 hour, 3 hours
				if ( $interval_part['interval'] > 1 ) {
					$result .= 's';
				}

				// Add delimiter after all parts except the last one.
				if ( $parts < $max_parts - 1 ) {
					$result .= $delimiter;
				}
				$parts ++;
			}
		}
		return $result;
	}