Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/DateTime.php
public static function MONTHOFYEAR($dateValue = 1)
    {
        $dateValue = Functions::flattenSingleValue($dateValue);

        if (empty($dateValue)) {
            $dateValue = 1;
        }
        if (is_string($dateValue = self::getDateValue($dateValue))) {
            return Functions::VALUE();
        } elseif ($dateValue < 0.0) {
            return Functions::NAN();
        }

        // Execute function
        $PHPDateObject = Date::excelToDateTimeObject($dateValue);

        return (int) $PHPDateObject->format('n');
    }
public static function MONTHOFYEAR($dateValue = 1)
    {
        $dateValue = Functions::flattenSingleValue($dateValue);

        if (empty($dateValue)) {
            $dateValue = 1;
        }
        if (is_string($dateValue = self::getDateValue($dateValue))) {
            return Functions::VALUE();
        } elseif ($dateValue < 0.0) {
            return Functions::NAN();
        }

        // Execute function
        $PHPDateObject = Date::excelToDateTimeObject($dateValue);

        return (int) $PHPDateObject->format('n');
    }
public static function MONTHOFYEAR ( $ dateValue = 1 ) { $ dateValue = Functions :: flattenSingleValue ( $ dateValue ) ; if ( empty ( $ dateValue ) ) { $ dateValue = 1 ; } if ( is_string ( $ dateValue = self :: getDateValue ( $ dateValue ) ) ) { return Functions :: VALUE ( ) ; } elseif ( $ dateValue < 0.0 ) { return Functions :: NAN ( ) ; } // Execute function $ PHPDateObject = Date :: excelToDateTimeObject ( $ dateValue ) ; return ( int ) $ PHPDateObject -> format ( 'n' ) ; }
MONTHOFYEAR.

Returns the month of a date represented by a serial number.
The month is given as an integer, ranging from 1 (January) to 12 (December).

Excel Function:
MONTH(dateValue)

@param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
PHP DateTime object, or a standard date string

@return int Month of the year
MONTHOFYEAR .