Function parseCronYear

Parses CronYear into a string.

Example

parseCronYear(1989); // "1989"
parseCronYear("*"); // "*"
parseCronYear({ every: 10, start: 1989 }); // "1989/10"
parseCronYear({ every: 10, start: "?" }); // "?/10"
parseCronYear([1989, 1991, 2015, 2020]); // "1989,1991,2015,2020"
parseCronYear({ from: 1989, to: 2020 }); // "1989-2020"
parseCronYear([
    1989,
    1989,
    1991,
    2015,
    2020,
    { from: 1989, to: 2020 },
]); // "1989,1991,2015,2020,1989-2020"

Returns

A string or undefined if invalid.