Show defaultValueDescription even if defaultValue is not set

[davidyuk]

Pull Request

Problem

I have an option that gets passed to the underlying library. I want to describe its default behaviour, but I can't pass any default value there except undefined. In case undefined the default value description is not printed in help.

const { program, Option } = require('commander');

const ttl = new Option('--ttl [ttl]', 'Transaction can be mined before provided height')
  .default(undefined, 'current height increased by 3');

program.addOption(ttl);
program.parse(process.argv);

Output:

$ node ./test.js --help
Usage: test [options]

Options:
  --ttl [ttl]  Transaction can be mined before provided height
  -h, --help   display help for command

Solution

I'm proposing to print defaultValueDescription even if it is provided without defaultValue. Though I'm not sure that it is not a misuse of "default value" concept.

Expected output:

$ ./test.js --help
Usage: test [options]

Options:
  --ttl [ttl]  Transaction can be mined before provided height (default: current height increased by 3)
  -h, --help   display help for command

ChangeLog

Added: show defaultValueDescription even if defaultValue is not set

This PR is supported by the Æternity Foundation

[shadowspawn]

Nice tidy PR.

It does feel enough like a misuse of "default value" concept that I am reluctant to add this.

... I can't pass any default value there except undefined.

Are you able to put in a placeholder default value (like false or null or even a symbol) and fix it up before passing to the underlying library? I appreciate this means you need to add an extra line of code in your code to do the work, so not free.

---

For example:

const { program, Option } = require('commander');

const ttl = new Option('--ttl [ttl]', 'Transaction can be mined before provided height')
  .default(false, 'current height increased by 3');

program.addOption(ttl);
program.parse(process.argv);
if (program.opts().ttl === false) program.setOptionValue('ttl', undefined); // replace placeholder value
console.log(program.opts());

% node index.js --help
Usage: index [options]

Options:
  --ttl [ttl]  Transaction can be mined before provided height (default: current height increased by 3)
  -h, --help   display help for command
% node index.js       
{ ttl: undefined }

[davidyuk]

This workaround worked in my case, thank you! You may close this PR

[shadowspawn]

Thanks for update @davidyuk