PhpSpreadsheet/tests/data/Shared/Date/FormatCodes.php

<?php

//  Excel Format Code                     Result
return [
    ['General', false],
    ['@', false],
    ['0', false],
    ['0.00', false],
    ['#,##0.00', false],
    ['#,##0.00_-', false],
    ['0%', false],
    ['0.00%', false],
    ['yyyy-mm-dd', true],
    ['yy-mm-dd', true],
    ['dd/mm/yy', true],
    ['d/m/y', true],
    ['d-m-y', true],
    ['d-m', true],
    ['m-y', true],
    ['mm-dd-yy', true],
    ['d-mmm-yy', true],
    ['d-mmm', true],
    ['mmm-yy', true],
    ['m/d/yy h:mm', true],
    ['d/m/y h:mm', true],
    ['h:mm AM/PM', true],
    ['h:mm:ss AM/PM', true],
    ['h:mm', true],
    ['h:mm:ss', true],
    ['mm:ss', true],
    ['h:mm:ss', true],
    ['i:s.S', true],
    ['h:mm:ss;@', true],
    ['yy/mm/dd;@', true],
    ['"$" #,##0.00_-', false],
    ['$#,##0_-', false],
    ['[$EUR ]#,##0.00_-', false],
    ['_[$EUR ]#,##0.00_-', false],
    ['[Green]#,##0.00;[Red]#,##0.00_-', false],
    ['#,##0.00 "dollars"', false],
];