Throw an error when the short flag for an option for longer than one character

[HopefulLlama]

In the .option(...) method, it takes a string flag which is comma separated, and describes a short and a long flag for passing arguments, such as:

  .option('-v, --version', 'Version information');

However, when given a short flag which is longer than one character, the program will still parse and execute, but cannot be accessed by its short flag.

For example:

  .option('-nv, --next-version', 'The next version');

It is impossible to use -nv on the command-line, as commander interprets this as two short flags concatenated together: -n and -v.

It would be better to throw an error to avoid the misleading set up of commander options.

[shadowspawn]

The documentation does mention the cli behaviour:

Short flags may be passed as a single arg, for example -abc is equivalent to -a -b -c.

but I agree it would be nice if commander warned you about the setup problem.

[HopefulLlama]

It does mention that, but it took me a long time to put two and two together.

I.e.: It does take some thinking to realise that a two character flag cannot work due to the short flag feature. It doesn't explicitly say so in the documentation.

I think an addition to the documentation, and an error or warning given when the misleading setup is actioned would be suitable.

[shadowspawn]

It now explicitly says single character in the documentation. (But still no warning about coding error, so feel free to keep this issue open.)

[shadowspawn]

Some more errors or warnings for coders (rather than users) is something we can improve in future. Closing this as have made an improvement with the addition to the README.