Edge cases

[vdanchenkov]

I've tested some edge cases and here is what we have currently:

style({})
// returns 
{ 'data-css-120drhm': '*' }
// inserts to stylesheet
'[data-css-120drhm] { null }'

select(' a', {})
// returns 
{ 'data-css-p8xeo9': '*' }
// inserts
'[data-css-p8xeo9] a { null }'

merge()
// returns 
{ 'data-css-120drhm': '[]' }
// inserts nothing to stylesheet

merge({})
// returns 
{ 'data-css-11ra3p3': '[{:}]' }
// inserts nothing to stylesheet

media('()', {})
// returns
{ 'data-css-11qittp': '*mq({:})' }
// inserts to stylesheet 
`
@media (){
      [data-css-11qittp] { null }
}`

media('()')
// returns 
{ 'data-css-1853dek': '*mq()' }
// inserts nothing to stylesheet

keyframes('bounce', {})
// returns 
'bounce_nc5hzc'
// inserts to stylesheet 
`
@-webkit-keyframes bounce_nc5hzc { }
@-moz-keyframes bounce_nc5hzc { }
@-o-keyframes bounce_nc5hzc { }
@keyframes bounce_nc5hzc { }
`

fontFace({})
// returns
undefined 
// inserts nothing to stylesheet

fontFace({fontStyle: 'normal'})
// returns
undefined 
// inserts to stylesheet
'@font-face { font-style:normal;}'

cssFor()
// returns 
''
// inserts nothing to stylesheet

attribsFor()
// returns 
''
// inserts nothing to stylesheet

I suggest:

1. For style/select/merge/media invocations from above return empty object. Add nothing to stylesheet.
2. Keyframes - keep as is
3. fontFace - current behaviour looks bad, but I'm not sure how to fix it.
4. cssFor and attribsFor are fine

[threepointone]

Thanks for diving into this!

[vdanchenkov]

Working on it as it's closely related to #41