type-args

The node.js options parser that plays well with TypeScript. To fetch the TypeScript interface from the option rules is extremely hard. However, type-args tries its best to make coding experience of command line option parsing more intelligent.

This is a minimalist implementation. And its algorithms are optimized. It's without annoying command interfaces.

Installation

Install this package with npm.

npm i type-args -s

Usage

Define your parsing rules

const rules = {
  'help': {
    alias: 'h',
    desc: 'display help.',
    type: 'boolean'
  },
  'version': {
    alias: 'v',
    desc: 'display version.',
    type: 'boolean'
  },
  'verbose': {
    alias: 'V',
    desc: 'verbose output.',
    type: 'boolean',
    default: true
  },
  'files': {
    alias: 'f',
    desc: 'the files to be transformed',
    type: 'string[]'
  }
}

The parsing rule is an object with camel cased flag names as keys, and descriptor objects as values. The descriptor object has 4 values.

• alias, single character string as the shortcut of the flag.
• desc, a string represents the description of the options.
• type, 'boolean' | 'number' | 'string' | 'number[]' | 'string[]'.
• default, the default value of the option.

Parsing ARGV

import { parse } from 'type-args';

const [options, args, unknownOptions] = parse(process.argv, rules);

• options is an object of parsed values.
• args is an array of non option tokens.
• unknownOptions is an array of undefined flags passed from argv.

Merging saved options

You can pass unlimited amount of saved options. Imagine you are the author of a large framework. You read options from package.json, from the .rcfile and user command line arguments. You may want merging those together with precedence like this:

default value < package.json < .rcfile < user command line arguments

type-args does what you want by accepting the ...third arguments.

License

MIT © Zhang Kai Yu