hmm, cljs :npm-deps installation appears to be removing other, valid deps that are in package.json and installed into node_modules. example w/ fairly minimal template with transitive React :npm-deps --

lein new re-view xyz;
cd xyz;
yarn install;

lein figwheel;

Not specific to shadow-cljs, replicated with left-pad as well

*appears to be a bug with NPM 5, https://github.com/npm/npm/issues/17929#issuecomment-319722758

so in NPM 5, running npm install <something> --save deletes other things in node_modules, even if they are listed in package.json, if npm install has not already been run. so anyone running yarn could encounter it. i think running npm install before any npm install <dep> --save would prevent this. blah.