Unknown option swallows a known one

[mfncooper]

Here's an example of everything working properly:

$ ./my-program.js --flag --foo hello
parsed =
{ flag: true,
  foo: 'hello',
  argv: 
   { remain: [],
     cooked: [ '--flag', '--foo', 'hello' ],
     original: [ '--flag', '--foo', 'hello' ],
     toString: [Function] } }

So far, so good. However, a mistaken name for the boolean option throws everything off, so if --myflag was mistakenly used instead of --flag, we get this:

$ ./my-program.js --myflag --foo hello
parsed =
{ myflag: '--foo',
  argv: 
   { remain: [ 'hello' ],
     cooked: [ '--myflag', '--foo', 'hello' ],
     original: [ '--myflag', '--foo', 'hello' ],
     toString: [Function] } }

Note how the mistyped 'myflag' option has now consumed the --foo option as its value, leaving what was intended as foo's value as part of 'remain'.

Since it can't be determined whether an unknown option is intended to have a value or not, and since nopt is designed to allow for the use of unknown options, it would make sense to check a possible value for an unknown option to see if it may, in fact, be the name of a known option. In the above example, this would mean that 'foo' would be correctly identified as an option name rather than being consumed as a value.

[isaacs]

I agree, that would be better. What about this case?

my-program --unknown1 --unknown2

Should that be:

{ unknown1: true
, unknown2: true
}

or

{ unknown1: "unknown2" }

Though it's a bit trickier, I'm tempted to say that the first makes more sense. Ie, an unknown option will not ever take a - prefixed thing as its argument. (If you want to make sure that it takes an argument, you can define it to do so.)

Thoughts?

[mfncooper]

Yes, that would make sense to me; that if you need to handle a -- prefixed value, you need to define the option, and otherwise any -- prefix introduces a new option.

[sbrandwoo]

I've just been bitten by this issue when using Grunt. Any options that Grunt itself doesn't know about are made available to the various tasks, meaning that there are a lot of unknown options being used in the system. As a result of this issue you can only use one --flag and it must be the last argument of the command.

I think the general solution of assuming that unknown arguments won't be prefixed with -- is a good one.

[isaacs]

Currently in nopt, any unknown argument must have a = to be assigned a value, otherwise it will be assumed to be a boolean. This is no longer an issue.