[jss-default-unit] transition-delay requires a unit even for a zero value

[timsnadden]

I was surprised to see that browsers (tested in chrome, firefox) treat a unitless 0 value for transition-delay as invalid. jss-default-unit only appends a unit to non-zero numbers leading to transition-delay not being set when I specify transitionDelay: 0.

[HenriBeck]

Interestingly the same applies to animation-delay.

Is this a big problem? Because if the property is invalid, it will behave the same as it's not applied which means it works the same as 0ms.

[timsnadden]

The reason it came up for us is that we wanted to override an existing setting on hover and it didn't take effect unless the value was set with a unit ('0ms')

On Mon, 24 Sep 2018 at 19:48, Henri notifications@github.com wrote:

Interestingly the same applies to animation-delay.

Is this a big problem? Because if the property is invalid, it will behave the same as it's not applied which means it works the same as 0ms.

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[kof]

The amount of inconsistencies in CSS is crazy.

[HenriBeck]

We could just simply add units to 0 as well.

[kof]

Not that simple, because some units actually require to be unitless, for e.g. opacity. If we implement #687 we will solve this issue as well.

[kof]

We need to maintain 2 lists: unitless and non-px props. Ideally we should generate them from mdn data like we do for the vendor prefixer.

[kof]

tbc in #687

[HenriBeck]

We would just need to remove the value !== 0 from: https://github.com/cssinjs/jss/blob/master/packages/jss-plugin-syntax-default-unit/src/index.js#L38

[kof]

That would convert everything to '0', I would try to keep numeric values as they are where possible.

[kof]

I think #687 will solve this case automatically, once it handles a unitless value with numbers and uses strings for the rest

[HenriBeck]

And it would convert everything to '0ms' for example where we have a default unit. This would solve the issue.

[kof]

you mean default unit? yes