Updating to v2 date-fns: NaN

Question

I'm updating the module date-fns from v1 to v2.

This helper method used to work:

const { format, parseISO, differenceInSeconds } = require("date-fns");

const newDateNow = () => {
    const date = new Date();
    return format(date, process.env.DATE_FORMAT);
};

// `process.env.DATE_FORMAT` is set to `yyyy-MM-dd HH:mm:ss`
console.log(ff) //prints: Thu Jul 21 2022 14:44:56 GMT+0200 (Central European Summer Time)
console.log(gg) //prints: 3600
console.log(newDateNow()) //prints: 2022-07-21 15:32:05

const isExpired = () => {
    const exp = differenceInSeconds(newDateNow(), ff);
    return parseInt(gg) > exp;
}

After the update to the module's v2 this generates the error: date-fns doesn't accept strings as date arguments. Please use 'parseISO' to parse strings. date-fns doesn't accept strings as date arguments. Please use 'parseISO' to parse strings. This pointing to the const exp line.

So I change that line to:

const exp = differenceInSeconds(newDateNow(), parseISO(ff));

This still generates the same error, so I change it to:

const exp = differenceInSeconds(parseISO(newDateNow()), parseISO(ff));

Now there is no error, but console.log(exp) prints NaN .

How should I implement this? Shouldn't I change the newDateNow method so that it's not necessary to use parseISO() on newDateNow() ?

Answer 1

parseISO() is a function for parsing a string formatted in ISO format, eg parseISO('2018-13-32') , so it's not what you need here.

Your first example should still be working. What behaviour are you seeing with it?

If you haven't seen already, the documentation is handy: https://date-fns.org/v2.28.0/docs/Getting-Started