minimist-lite

parse argument options

This module is the guts of optimist's argument parser without all the fanciful decoration.

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This repo is to keep the seemingly abandoned minimist package alive and up to date.

All credits go to James Halliday

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Installation

With npm do:

npm install minimist-lite

With yarn do:

yarn add minimist-lite

License

MIT License. See LICENSE for details.

Examples

See example/parse.js:

var argv = require('minimist-lite')(process.argv.slice(2));

console.log(argv);

Running node example/parse.js with arguments shows how they are parsed by minimist:

No arguments

With no arguments minimist returns an object with a single key "_" (underscore) with a value of an empty array:

$ node example/parse.js
{ _: [] }

Arguments without dashes

Using arguments with no dashes adds them to the "_" array in the object returned by minimist:

$ node example/parse.js abc def
{ _: [ 'abc', 'def' ] }

Single-letter options

A single dash starts a single-letter option that are boolean by default:

$ node example/parse.js -a -b -c
{ _: [], a: true, b: true, c: true }

Single-letter options can be joined together:

$ node example/parse.js -abc
{ _: [], a: true, b: true, c: true }

When a single-letter option is followed by a value with no dashes, the option gets that value in the returned object instead of a boolean value:

$ node example/parse.js -a beep -b boop
{ _: [], a: 'beep', b: 'boop' }

Numeric values can be joined with single-letter options:

$ node example/parse.js -a 1 -b2
{ _: [], a: 1, b: 2 }

Multi-letter options

Multi-letter options start with double dashes and they are boolean by default:

$ node example/parse.js --abc --def
{ _: [], abc: true, def: true }

Values can follow multi-letter options after a space or equal sign:

$ node example/parse.js --abc 1 --def=2
{ _: [], abc: 1, def: 2 }

--no- prefix handling

Options with the prefix --no- will be treated as a flag that has the value false by default:

$ node example/parse.js --no-abc
{ _: [], abc: false }

$ node example/parse.js --no-abc true
{ _: ['true'], abc: false }

Mixed styles

All of those styles can be used together:

$ node example/parse.js -x 3 -y 4 -n5 -abc --beep=boop --hoo:haa foo bar baz
{ _: [ 'foo', 'bar', 'baz' ],
  x: 3,
  y: 4,
  n: 5,
  a: true,
  b: true,
  c: true,
  hoo: [haa],
  beep: 'boop' }

The default parsing of the arguments can be changed by using the second argument to the parsing method, see below.

Repeated options

If an option is provided more than once, the returned object value for that option will be an array (rather than a boolean or a string):

$ node example/parse.js --foo=bar --foo=baz
{ _: [], foo: [ 'bar', 'baz' ] }

Methods

Minimist exports a single method:

var parseArgs = require('minimist-lite');

var argv = parseArgs(args, opts={})

Return an argument object argv populated with the array arguments from args.

argv._ contains all the arguments that didn't have an option associated with them, or an empty array if there were no such arguments.

Numeric-looking arguments will be returned as numbers unless opts.string or opts.boolean is set for that argument name.

Any arguments after '--' will not be parsed and will end up in argv._.

Options

options can be:

• opts.string - a string or array of strings with argument names to always treat as strings

• opts.array - a string or array of strings argument names to always treat as array values

• opts.boolean - a boolean, string or array of strings to always treat as booleans. if true will treat all double hyphenated arguments without equal signs as boolean (e.g. affects --foo, not -f or --foo=bar)

• opts.alias - an object mapping string names to strings or arrays of string argument names to use as aliases

• opts.default - an object mapping string argument names to default values

• opts.stopEarly - when true, populate argv._ with everything after the first non-option

• opts['--'] - when true, populate argv._ with everything before the -- and argv['--'] with everything after the --. Here's an example:

  > require('./')('one two three -- four five --six'.split(' '), { '--': true })
  { _: [ 'one', 'two', 'three' ],
    '--': [ 'four', 'five', '--six' ] }
  

  Note that with opts['--'] set, parsing for arguments still stops after the --.

• opts.unknown - a function which is invoked with a command line parameter not defined in the opts configuration object. If the function returns false, the unknown option is not added to argv.