Using 'filter' (or other native array methods) as a command causing error

[jonathanrdelgado]

Came across an error today when using filter as a command input.

Simple reproduction:

com.command('seed <tpl>')
    .action(function(tpl){});

Just running the command <script> seed filter will cause a module not found error, no special coding required.

Error: Cannot find module 'c:\Users\...\bin\cmd-filter'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:906:3

It is caused by line 380 of commander's index.js - Even if the this._execs array is empty, calling this._execs['filter'] will return the native function, thus causing the argument to be true and creating this error.

Best solution in my opinion is double checking the value to make sure it is not a function. If you would like, I can throw in a PR.

Thank you for your time.

[thethomaseffect]

Absolutely, good catch! 👍

[startswithaj]

Resolves #206