Allow an empty %css rule?

[davesnx]

I often find myself wanting to add some rules conditionally. Because I often use switch statement, (but it's true for ifs as well), all branches should have the same type. Because of that, I find myself with a need to add a property as a default value on the other side.

Example

let margin = (isLeft) =>
  switch isLeft {
  | true => %css("margin-left: 10px;")
  | false => %css("")
  }

module Component = %styled.div([
  %css("background-color: red;"),
  %css("border-radius: 20px;"),
  %css("box-sizing: border-box;"),
  margin(All),
])

%css("") is an invalid rule, since it's defined to not accept empty declarations.

In order to solve that I have 2 ideas:

1. Support empty declarations on %css extension
2. Create an %css.empty that transforms into an empty rule, such as CssJs.unsafe("", "")

---

Conclusion

Not particularly fan of either, that's why I open the issue. Both have problems of discovery and aren't obvious.