multi repo

npm registry has pretty bad error management. Put wrong registry url and all I got was cryptic error (registry json bla bla)
also problem with windows and npm, downgraded npm to v5.3 and node to 8.2

rollup

some shitty error message (invalid token) solved by removing node_modules and reinstalling
and having rollup in global (don't know if that played a role though)

browserify and import/export

be careful about syntax... specially for default export (ideal is to just never use default export but some third-party libraries do, so impossible to avoid it entirely)
- for rx, import Rx from "rx" instead of import * as Rx
  - otherwise only works for webpack, not for rollup
for cycle-snabbdom, include snabbdom-to-html, and snabbdom too
- look at some build doc from the library
- or look at the error message (first option is best though)
- that means also write build doc for my own library!!
had to configure browserify to use babelify transform in the package.json, for some reasons stopped working with the CLI flag --transform... Maybe a hidden change of version of something? Life is a mystery.

formatting object

Be sure to have maxDepth set (I set 3), otherwise object like DOM or observable take an eternity to display.

build issues

remove node_module, force clean the npm cache (npm clean cache --force, or sth like that)
update version (that worked for rollup uglyfy plugin)
pray