Conditional resolution

Is there any solution of implying `if..else` logic with templates?

As (as far as I know) we can't put `if` statement directly in body of `${ }`, there is probably a need for dedicated `if` function e.g. `bel.if(condition, onTrue, onFalse)`.

Is something as that envisioned, or maybe already there's some solution (or convention) coined for that?

Unfortunately [wiki](https://github.com/shama/bel/wiki) is very silent on that very common use case.