Possible typing for string input in SignJWT.setExpirationTime

[trentcharlie]

While working with SignJWT.setExpirationTime I found myself writing the following type to add type safety in a helper function I was using to generate JWT tokens.

type TimeSpan = `${number} ${
    | 'seconds'
    | 'secs'
    | 's'
    | 'minutes'
    | 'mins'
    | 'm'
    | 'hours'
    | 'hrs'
    | 'h'
    | 'days'
    | 'd'
    | 'weeks'
    | 'w'
    | 'years'
    | 'yrs'
    | 'y'}`

I am wondering if this could be a useful addition to the library.