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],
];