isValid to validate timestamp

[loretoparisi]

The isValid works ok, but does not take in account the validation of timestamp and randomness separately, hence I suggest this enhancement to validate the timestamp part:

function isValid(id) {
    var valid = (
        typeof id === "string" &&
        id.length === TIME_LEN + RANDOM_LEN &&
        id
            .toUpperCase()
            .split("")
            .every(char => ENCODING.indexOf(char) !== -1)
    );
    try { valid &= isTimestamp(decodeTime(id)); } catch(error) { valid = false }
    return valid;
}

where decodeTime is ulid.decodeTime and utils are

function isNumeric(n) {
    return !isNaN(parseFloat(n)) && isFinite(n);
}
function isTimestamp(_timestamp) {
    const newTimestamp = new Date(_timestamp).getTime();
    return isNumeric(newTimestamp);
}

This should be enough to guaratee that both ulid and monotonic are valid ulid with timestamp and randomness information.