src/Carbon/CarbonInterval.php
public function isEmpty()
    {
        return $this->years === 0 &&
            $this->months === 0 &&
            $this->dayz === 0 &&
            !$this->days &&
            $this->hours === 0 &&
            $this->minutes === 0 &&
            $this->seconds === 0 &&
            $this->microseconds === 0;
    }
public function isEmpty()
    {
        return $this->years === 0 &&
            $this->months === 0 &&
            $this->dayz === 0 &&
            !$this->days &&
            $this->hours === 0 &&
            $this->minutes === 0 &&
            $this->seconds === 0 &&
            $this->microseconds === 0;
    }
public function isEmpty ( ) { return $ this -> years === 0 && $ this -> months === 0 && $ this -> dayz === 0 && ! $ this -> days && $ this -> hours === 0 && $ this -> minutes === 0 && $ this -> seconds === 0 && $ this -> microseconds === 0 ; }
Returns true if the interval is empty for each unit.

@return bool
Returns true if the interval is empty for each unit .