mri

Quickly scan for CLI flags and arguments

This is a fast and lightweight alternative to minimist and yargs-parser.

It only exists because I find that I usually don't need most of what minimist and yargs-parser have to offer. However, mri is similar enough that it might function as a "drop-in replacement" for you, too!

See Comparisons for more info.

$ npm install --save mri

$ demo-cli --foo --bar=baz -mtv -- hello world

const mri = require('mri');

const args = process.argv.slice(2);

mri(args);
//=> { _: ['hello', 'world'], foo:true, bar:'baz', m:true, t:true, v:true }

mri(args, { boolean:['bar'] });
//=> { _: ['baz', 'hello', 'world'], foo:true, bar:true, m:true, t:true, v:true }

mri(args, {
  alias: {
    b: 'bar',
    foo: ['f', 'fuz']
  }
});
//=> { _: ['hello', 'world'], foo:true, f:true, fuz:true, b:'baz', bar:'baz', m:true, t:true, v:true }

Type: array
Default: []

An array of arguments to parse. For CLI usage, send process.argv.slice(2). See process.argv for info.

Type: object
Default: {}

An object of keys whose values are a string or array of aliases. These will be added to the parsed output with matching values.

Type: array|string
Default: []

A single key (or array of keys) that should be parsed as Booleans.

Type: object
Default: {}

An key:value object of defaults. If a default is provided for a key, its type (typeof) will be used to cast parsed arguments.

mri(['--foo', 'bar']);
//=> { _:[], foo:'bar' }

mri(['--foo', 'bar'], {
  default:{ foo:true, baz:'hello', bat:42 }
});
//=> { _:['bar'], foo:true, baz:'hello', bat:42 }

Note: Because --foo has a default of true, its output is cast to a boolean. This means that foo:true, which makes 'bar' an extra argument (_ key).

Type: array|string
Default: []

A single key (or array of keys) that should be parsed as Strings.

• mri is 2.5x faster (see benchmarks)
• Numerical values are cast as Numbers when possible
  • A key (and its aliases) will always honor opts.boolean or opts.string
• Short flag groups are treated as Booleans by default:

  minimist(['-abc', 'hello']);
  //=> { _:[], a:'', b:'', c:'hello' }
  
  mri(['-abc', 'hello']);
  //=> { _:[], a:true, b:true, c:'hello' }

• Missing options:
  • opts.stopEarly
  • opts.unknown
  • opts['--']
• Ignores newlines (\n) within args (see test)
• Ignores slashBreaks within args (see test)
• Ignores dot-nested flags (see test)

• mri is 20x faster (see benchmarks)
• Numerical values are cast as Numbers when possible
  • A key (and its aliases) will always honor opts.boolean or opts.string
• Missing options:
  • opts.array
  • opts.config
  • opts.coerce
  • opts.count
  • opts.envPrefix
  • opts.narg
  • opts.normalize
  • opts.configuration
  • opts.number
  • opts['--']
• Missing parser.detailed() method
• No additional configuration object

mri
  --> 328,452 ops/sec ±0.28% (92 runs sampled)
yargs
  --> 16,014 ops/sec ±0.69% (94 runs sampled)
minimist
  --> 131,896 ops/sec ±0.92% (90 runs sampled)

MIT © Luke Edwards