I'm not sure if simple text in the root is supported.
https://codesandbox.io/s/static-0bhft

but I stumbled on a build error once I tried to use the babel-plugin-htm for a simple string in the root.

html`Here's a list of items: Count: ${22}`

This is a quick fix, just checks if the node passed in transform is really a node and else puts it through the childMapper.

luwes/sinuous@485c944