In general, JavaScript code should not distinguish +0 and -0 IMHO. But here’s an exception!
Intl.RelativeTimeFormat plans to treat +0 and -0 differently:
+0 → future
-0 → past
This way, the positive/negative sign has the same meaning as for other numbers passed to this API.
ALT // Set up a relative time formatter using the English locale.
const rtf = new Intl.RelativeTimeFormat('en');
// Positive zero is interpreted as the future.
rtf.format(0, 'day');
// → 'in 0 days'
// Negative zero is interpreted as the past.
rtf.format(-0, 'day');
// → '0 days ago'