[SOLVED] Unnamed parameter with commander.js (positional arguments)

Unnamed parameter with commander.js (positional arguments)

I am currently taking a look at commander.js as I want to implement a CLI using Node.js.

Using named parameters is easy, as the example of a "pizza" program shows:

program
  .version('0.0.1')
  .option('-p, --peppers', 'Add peppers')
  .option('-P, --pineapple', 'Add pineapple')
  .option('-b, --bbq', 'Add bbq sauce')
  .option('-c, --cheese [type]', 'Add the specified type of cheese [marble]', 'marble')
  .parse(process.argv);

Now, e.g., I can call the program using:

$ app -p -b

But what about an unnamed parameter? What if I want to call it using

$ app italian -p -b

? I think this is not so very uncommon, hence providing files for the cp command does not require you to use named parameters as well. It's just

$ cp source target

and not:

$ cp -s source -t target

How do I achieve this using commander.js?

And, how do I tell commander.js that unnamed parameters are required? E.g., if you take a look at the cp command, source and target are required.

Solution

With the present version of commander, it's possible to use positional arguments. See the docs on argument syntax for details, but using your cp example it would be something like:

program
.version('0.0.1')
.arguments('<source> <target>')
.action(function(source, target) {
    // do something with source and target
})
.parse(process.argv);

This program will complain if both arguments are not present, and give an appropriate warning message.