用JSON表示命令行参数的好方法是什么？

Question

I'm trying to make improvements to the grunt-closure-linter npm project (so I can actually use it in a productive fashion), and here's where I'm stuck on it now:

I want to specify a way to pass options through to the command line gjslint which is the driver for the Closure Linter.

USAGE: /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/bin/gjslint [flags]

flags:

closure_linter.checker:
  --closurized_namespaces: Namespace prefixes, used for testing ofgoog.provide/require
    (default: '')
    (a comma separated list)
  --ignored_extra_namespaces: Fully qualified namespaces that should be not be reported as extra
    by the linter.
    (default: '')
    (a comma separated list)

closure_linter.common.simplefileflags:
  -e,--exclude_directories: Exclude the specified directories (only applicable along with -r or
    --presubmit)
    (default: '_demos')
    (a comma separated list)
  -x,--exclude_files: Exclude the specified files
    (default: 'deps.js')
    (a comma separated list)
  -r,--recurse: Recurse in to the subdirectories of the given path;
    repeat this option to specify a list of values

closure_linter.ecmalintrules:
  --custom_jsdoc_tags: Extra jsdoc tags to allow
    (default: '')
    (a comma separated list)

closure_linter.error_check:
  --jslint_error: List of specific lint errors to check. Here is a list of accepted values:
    - all: enables all following errors.
    - blank_lines_at_top_level: validatesnum
...

As you can see this thing has many options!

The grunt task is pretty concise so I was quickly able to find where to inject this into the command line to get this done, however I'm wondering how best to go about converting a sane JSON representation like

{
    "max_line_length": '120',
    "summary": true
}

into a commandline options string:

--max_line_length 120 --summary

It's not even clear that there is any standard way to represent it with JSON. It did occur to me that somebody else might not consider it sane to specify a plain no-param argument using the value true .

I figure I guess I could fall back to a more unambiguous but less structured

[ "--max_line_length", "120", "--summary" ]

or some such, though that's hardly practical considering how tempted I would be to avoid the commas and quotes and leave it as a plain string.

How is this supposed to get defined?

Answer 1

I've adapted my module dargs , which converts an object of options to an array of command-line arguments, for your use-case.

Just pass it an object with camelCased keys and it will do the rest.

function toArgs(options) {
    var args = [];

    Object.keys(options).forEach(function (key) {
        var flag;
        var val = options[key];

        flag = key.replace(/[A-Z]/g, '_$&').toLowerCase();

        if (val === true) {
            args.push('--' + flag);
        }

        if (typeof val === 'string') {
            args.push('--' + flag, val);
        }

        if (typeof val === 'number' && isNaN(val) === false) {
            args.push('--' + flag, '' + val);
        }

        if (Array.isArray(val)) {
            val.forEach(function (arrVal) {
                args.push('--' + flag, arrVal);
            });
        }
    });

    return args;
};

Example:

toArgs({ maxLineLength: 120 });

Outputs:

['--max_line_length', '120']