These examples demonstrate current issues with crx package.
$ node example-missing-key.js
Error Impossible to generate a public key: privateKey option has not been defined or is empty.
$ npm run get-key
> crx-issue@1.0.0 get-key .
> crx keygen .
Key file has been generated at ./key.pem
$ node example-relative-path.js
Error { Error: Cannot find module 'dummy-extension/manifest.json'
at Function.Module._resolveFilename (module.js:469:15)
at Function.Module._load (module.js:417:25)
at Module.require (module.js:497:17)
at require (internal/module.js:20:19)
... }
$ node example-ok.js
OK
Public domain.