nigthwatch command failed with "Cannot find module 'optimist'" ( v1.0.4 )

[dragon3]

I got the following error when I try to run the nightwatch command (v1.0.4):

$ nightwatch --help
   Cannot find module 'optimist'
       at Function.Module._resolveFilename (internal/modules/cjs/loader.js:548:15)
       at Function.Module._load (internal/modules/cjs/loader.js:475:25)
       at Module.require (internal/modules/cjs/loader.js:598:17)
       at require (internal/modules/cjs/helpers.js:11:18)
       at Module._compile (internal/modules/cjs/loader.js:654:30)
       at Object.Module._extensions..js (internal/modules/cjs/loader.js:665:10)
       at Module.load (internal/modules/cjs/loader.js:566:32)
       at tryModuleLoad (internal/modules/cjs/loader.js:506:12)
       at Function.Module._load (internal/modules/cjs/loader.js:498:3)
error Command failed with exit code 2.

It looks like the dependency optimist removed unintentionally in e037711 .