otps

Command line argument parser with format inspired by esbuild

• value: --format esm or short -f esm
• flag: -v, -vPfz or -vvv
• key/value: --format:ts esm or -f:ts esm
• key: --external:fs or short -e:fs

Supports sub-commands, see below.

Getting started

Install otps using pnpm:

pnpm add otps

Or npm:

npm install --save otps

Let's get started by writing a simple command line application that takes one parameter named format (or f for short).

First, create a app.js file:

import { parse, Value } from 'otps'
const [params, args] = parse(process.argv.slice(2), {
  format: Value(),
  f: 'format',
})

Then run the program:

node app.js --format esm index.ts
# => params: { format: 'esm' }
#    args: ['index.ts']

Or equivalent:

node app.js -f esm index.ts
# => params: { format: 'esm' }
#    args: ['index.ts']

Sub commands

Let's create a more advanced app that uses a verbose parameter (with a v alias) and a sub-commands build with a level parameter that takes one of two values debug or info.

Create a subcmdapp.js file:

import { parse, Flag, OneOf } from 'otps'
const [params, args] = parse(process.argv.slice(2), {
  verbose: Flag(),
  v: 'verbose',
  build: {
    level: OneOf('debug', 'info'),
  },
})

Then run the program:

node subcmdapp.js -vvv build --level info index.ts
# => params: { verbose: 3, build: { level: 'info' } }
#    args: ['index.ts']

Using cmds

For easier managment of sub-commands, use cmds.

Create a cmdsapp.js file:

import { parse, Value, cmds } from 'otps'

const [params, args] = parse(process.argv.slice(2), {
  build: {
    format: Value(),
    production: {
      version: Value(),
    },
  },
})

cmds(params, args)({
  build(params, args) {
    const format = params.format
    cmds(params, args)({
      production(params, args) {
        const version = params.version
        console.log(`production build: ${format}, name: app@${version}`)
        console.log(args)
      }
    }, (params, args) => {
      console.log(`development build: ${format}, name: app@dev`, args)
      console.log(args)
    })
  }
})

Then run the program:

node cmdsapp.js build --format esm production --version 1.0 src/index.ts
# => production build: esm, name: [email protected]
#    ['src/index.ts']

node cmdsapp.js build --format esm src/index.ts
# => production build: esm, name: app@dev
#    ['src/index.ts']

Parameters

Parameters are defined using the following syntax: { name: Func } or with aliases { name: Func, n: 'name' }. Where Func is one of:

Value():

parse(['--format', 'esm'], { format: Value() })
// => { format: 'esm' }

OneOf(string | regex, ...):

parse(['--level', 'dEbUg'], { level: OneOf(/^debug$/i, 'info') })
// => { level: 'dEbUg' }

Flag():

parse(['-v'], { v: Flag() })
// => { v: true }
parse(['-vvv'], { v: Flag() })
// => { v: 3 }
parse(['-vP'], { v: Flag(), P: Flag() })
// => { v: true, P: true }

Key():

parse(['--external:fs'], { external: Key() })
// => { external: { fs: true } }
parse(['--external:fs', '-e:fs'], { external: Key(), e: 'external' })
// => { external: { fs: 2 } }

Key(Value() | OneOf(...)):

parse(['--define:DEBUG', 'true'], { define: Key(Value()) })
// => { define: { DEBUG: 'true' } }
parse(['--define:LEVEL', 'debug'], { define: Key(OneOf('debug', 'info')) })
// => { define: { LEVEL: 'debug' } }

Maybe(Value() | OneOf(...)):

parse(['--format'], { format: Maybe(Value()) })
// => { format: true }
parse(['--format', 'esm'], { format: Maybe(Value()) })
// => { format: 'esm' }
parse(['--level'], { level: Maybe(OneOf('debug', 'info')) })
// => { level: true }
parse(['--level', 'info'], { level: Maybe(OneOf('debug', 'info')) })
// => { level: 'info' }

Many(Value() | OneOf(...) | Maybe(...)):

parse(['--format', 'esm', '--format', 'cjs'], { format: Many(Value()) })
// => { format: ['esm', 'cjs'] }
parse(['--format', '--format', 'cjs'], { format: Many(Maybe(OneOf('esm', 'cjs'))) })
// => { format: [true, 'cjs'] }