WIP: Keep command out of program.args and add unknown to .action params

[shadowspawn]

Pull Request

I have not written any new tests or updated docs yet. This is a draft PR to show current code.

Problem

There are problems with the processing of arguments to call .action:

• extra arguments are ignored and the first one is overwritten
• the passed array of arguments is mutated, but that ultimately affects program.args, including especially inappropriately adding the command object into that array
• the combination of issues makes it hard for client code to detect extra arguments

See: #386 #749 #1000

var program = require('commander');

  program
    .option('-v, --verbose', 'Enable verbose output')
    .usage('[options] [command]')

  program
    .command('sub <something>')
    .action(function(oneArgument, cmd, extraArguments) {
      console.log(`Expected argument is: ${oneArgument}`);
      console.log('Extra arguments: ', extraArguments);
      console.log('program.args: ', program.args);
    });

program.parse(["node", "some-file.js", "-v", "sub", 1, 2, 3, 4, 5, 6, 7, 8, 9]);

$ node index.js 
Expected argument is: 1
Extra arguments:  3
program.args:  [ 1,
  Command {
    ... dump of command object!
  3,
  4,
  5,
  6,
  7,
  8,
  9 ]

Solution

Changed code to prepare parameters for .action in a separate array without changing passed array. Pass unexpected parameters to .action as an array rather than just tagged on end.

$ node index.js 
Expected argument is: 1
Extra arguments:  [ 2, 3, 4, 5, 6, 7, 8, 9 ]
program.args:  [ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]

[shadowspawn]

Closing in favour of #1048 where reworked changes after move to Jest.