feat(#78): allow cookieExpiresAfterDays as a function

[gtnsimon]

This allow to conditionally define cookie duration based on user consent.

Here a snippet function to control cookie duration using a function:

// orejime.config.js
const config = {
  /* ... */
  cookieExpiresAfterDays(consents, config) {
		if (consents) {
			// ignore required apps (true is enforced)
			const consentableApps = config.apps
				.filter((app) => app.required !== true)
				.map((app) => app.name);
			// get selected user apps
			const userConsents = Object.values(
				Object.fromEntries(
					Object.entries(consents).filter(([name]) =>
						consentableApps.includes(name)
					)
				)
			);

			// cookie will expire after 90 days for users who accepted all apps
			if (userConsents.every((value) => value === true)) {
				return 90;
			}

			// otherwise (all apps refused or not all accepted) cookie will expire after 30 days
			return 30;
		}
	},
  /* ... */
}

Resolves: #78

[felixgirault]

I would maybe remove this test and use a default value in setCookie like before.
This way any falsy or 0 value would be set to the default.

setCookie(
	this.cookieName,
	value,
	cookieExpiresAfterDays || 120,
	this.config.cookieDomain
);

[felixgirault]

cookieExpiresAfterDays could then be a const var.

[gtnsimon]

I agree with falsies values but 0 as an integer has a meaning for cookie expiration which ends when browser is closed. Using cookieExpiresAfterDays || 120 will replace 0 to 120 which may not be the expected behavior by the end developer.

To not break existing installations, the default could apply to non-functional cookieExpiresAfterDays (like before this feature). When used as a function it'll be up to the developer to explicitly return a value if he don't want a session cookie.

[felixgirault]

I didn't know about this behavior with 0, given the old implementation I thought it was kind of invalid.
I'm kind of torn here, it would be a breaking change to modify the current behavior, but it seems odd to have different behaviors for different methods...