TypeError: optional is not a fcuntion

[JiewenLL]

When I entered this: sudo btlejuice -u -w

/usr/local/lib/node_modules/btlejuice/bin/cmd_btlejuice.js:21
var btim = optional('btim');
^

TypeError: optional is not a function
at Object. (/usr/local/lib/node_modules/btlejuice/bin/cmd_btlejuice.js:21:12)
at Module._compile (module.js:577:32)
at Object.Module._extensions..js (module.js:586:10)
at Module.load (module.js:494:32)
at tryModuleLoad (module.js:453:12)
at Function.Module._load (module.js:445:3)
at Module.runMain (module.js:611:10)
at run (bootstrap_node.js:387:7)
at startup (bootstrap_node.js:153:9)
at bootstrap_node.js:500:3

Can I get some help. Is this an installation problem?

Thanks!!