Joi.number allows Infinity

[dbrockman]

Feature request for a breaking change. Joi version 4.9.0

I'm not sure if this is the desired behaviour or not. It seems to me like Infinity should be rejected just like NaN.

This seems a bit awkward in order to validate that the value is a finite number:

joi.number().invalid(Infinity, -Infinity)

[kanongil]

This seems like a non-issue. Infinity is a perfectly valid number, where typeof Infinity === 'number'. As such I would expect Infinity to validate.

[Marsup]

All mathematical operations I tried on Infinity generate perfectly valid results, so I'd tend to agree with @kanongil. What bothers you ? That it's not serializable ?

[dbrockman]

I almost didn't post the issue in the first place because I agree that Infinity is a valid number but it's far more likely the result of a bug than a valid value.

0 / 0  // NaN
1 / 0  // Infinity
-1 / 0 // -Infinity

When I validate numbers I use isFinite() instead of ! isNaN() to guard against infinity.

But maybe this is outside of the scope of Joi.

[Marsup]

I'll probably make that change, serialization poses a serious problem since it produces unexpected results.
Let's say you're validating Joi.object({ val: Joi.number().required() }) before stringifying.
For { val: Infinity } you'll get { val: null } which is not what I would expect.

[kanongil]

Looking at it again, Joi explicitly fails on string conversions for "Infinity". This leads me to think that when Infinity validates it is a straight up bug. In any case it's a weird inconsistency.

[Marsup]

Like I said Infinity is not serializable, that can't be worked around without a special case, but anyway I'd rather not support an edge case that breaks people's expectations.

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