Wrong return type for parseISO

Hi,

I use the parseISO function like this :

      const date = parseISO(val)
      if (date === "Invalid Date") return false

TS compiler returns an error because parseISO is supposed to return a Date. But in fact, it can return a string with the value “Invalid Date”.

In my idea, it would be better to return an exception. But at least, the definition should be : parseInfo(...): Date | string.

[fturmel]

@marcbachmann If it’s good enough for your use case, that’s great.

I do think it’s important to point out these details for others stumbling on this issue in the future. They might not be running this in node exclusively, or might care about dates before 1970.

[pom421]

For future reader, my need was to validate a date format in ISO in a payload API JSON, so I decided to not use date-fns but only use the regex : /^(\d{4})-(\d{2})-(\d{2})$/.