1. It doesn't, but mutation is generally less likely to happen in an expression context than in a statement context (partly by convention, but also it's common

1. It doesn't, but mutation is generally less likely to happen in an expression context than in a statement context (partly by convention, but also it's common to eg. lint against assignments in expression contexts) 2. Personally I think it will be quite elegant. JSX itself is an expression, not a function, so it would only ever be the last stage in a pipe (or the context in which a pipe expression is embedded). Note that it would be useful even for just (for example) string transformations that happen to be deeply embedded in some JSX, not exclusively contexts where JSX is directly involved 2b. I didn't know about do-expressions; those look potentially exciting