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Smooth (CLI) operator 🎶

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Package description

What is sade?

The sade npm package is a lightweight command-line interface (CLI) library for building command-line applications in Node.js. It provides a simple and fluent API to define commands, options, and their associated actions. Sade allows developers to easily parse command-line arguments, manage sub-commands, and create user-friendly CLI tools.

What are sade's main functionalities?

Command Definition

This feature allows you to define a command with required and optional arguments. The 'describe' method is used to provide a description for the command, and the 'option' method is used to define options. The 'action' method is where the functionality for the command is implemented.

const sade = require('sade');

const prog = sade('mycli <input>').
  describe('Process the input file.').
  option('-o, --output', 'Specify output file').
  action((input, opts) => {
    console.log(`Processing ${input} with output ${opts.output}`);



This feature demonstrates how to define sub-commands within a CLI application. Each sub-command can have its own description and action handler.

const sade = require('sade');

const prog = sade('mycli').

  describe('Build the project.').
  action(() => {
    console.log('Building the project...');

  describe('Deploy the project.').
  action(() => {
    console.log('Deploying the project...');


Option Parsing

This feature shows how to parse options passed to the CLI. Options can be defined with a short and long version, and their presence can be checked within the action handler.

const sade = require('sade');

const prog = sade('mycli').
  option('-v, --verbose', 'Enable verbose output').
  action(opts => {
    if (opts.verbose) {
      console.log('Verbose mode is on.');


Other packages similar to sade



sade Build Status

Smooth (CLI) Operator 🎶

Sade is a small but powerful tool for building command-line interface (CLI) applications for Node.js that are fast, responsive, and helpful!

It enables default commands, git-like subcommands, option flags with aliases, default option values with type-casting, required-vs-optional argument handling, command validation, and automated help text generation!

Your app's UX will be as smooth as butter... just like Sade's voice. 😉


$ npm install --save sade



#!/usr/bin/env node

const sade = require('sade');

const prog = sade('my-cli');

  .option('--global, -g', 'An example global flag')
  .option('-c, --config', 'Provide path to custom config', 'foo.config.js');

  .command('build <src> <dest>')
  .describe('Build the source directory. Expects an `index.js` entry file.')
  .option('-o, --output', 'Change the name of the output file', 'bundle.js')
  .example('build src build --global --config my-conf.js')
  .example('build app public -o main.js')
  .action((src, dest, opts) => {
    console.log(`> building from ${src} to ${dest}`);
    console.log('> these are extra opts', opts);



$ my-cli --help

    $ my-cli <command> [options]

  Available Commands
    build    Build the source directory.

  For more info, run any command with the `--help` flag
    $ my-cli build --help

    -v, --version    Displays current version
    -g, --global     An example global flag
    -c, --config     Provide path to custom config  (default foo.config.js)
    -h, --help       Displays this message

$ my-cli build --help

    Build the source directory.
    Expects an `index.js` entry file.

    $ my-cli build <src> [options]

    -o, --output    Change the name of the output file  (default bundle.js)
    -g, --global    An example global flag
    -c, --config    Provide path to custom config  (default foo.config.js)
    -h, --help      Displays this message

    $ my-cli build src build --global --config my-conf.js
    $ my-cli build app public -o main.js


  • Define your global/program-wide version, options, description, and/or examples first.
    Once you define a Command, you can't access the global-scope again.

  • Define all commands & options in the order that you want them to appear.
    Sade will not mutate or sort your CLI for you. Global options print before local options.

  • Required arguments without values will error & exit
    An Insufficient arguments! error will be displayed along with a help prompt.

  • Don't worry about manually displaying help~!
    Your help text is displayed automatically... including command-specific help text!

  • Automatic default/basic patterns
    Usage text will always append [options] & --help and --version are done for you.

  • Only define what you want to display!
    Help text sections (example, options, etc) will only display if you provide values.


Subcommands are defined & parsed like any other command! When defining their usage, everything up until the first argument ([foo] or <foo>) is interpreted as the command string.

They should be defined in the order that you want them to appear in your general --help output.

Lastly, it is not necessary to define the subcommand's "base" as an additional command. However, if you choose to do so, it's recommended that you define it first for better visibility.

const prog = sade('git');

// Not necessary for subcommands to work, but it's here anyway!
  .describe('Manage set of tracked repositories')
  .action(opts => {
    console.log('~> Print current remotes...');

  .command('remote add <name> <url>', 'Demo...')
  .action((name, url, opts) => {
    console.log(`~> Adding a new remote (${name}) to ${url}`);

  .command('remote rename <old> <new>', 'Demo...')
  .action((old, nxt, opts) => {
    console.log(`~> Renaming from ${old} to ${nxt}~!`);

Single Command Mode

In certain circumstances, you may only need sade for a single-command CLI application.

Note: Until v1.6.0, this made for an awkward pairing.

To enable this, you may make use of the isSingle argument. Doing so allows you to pass the program's entire usage text into the name argument.

With "Single Command Mode" enabled, your entire binary operates as one command. This means that any prog.command calls are disallowed & will instead throw an Error. Of course, you may still define a program version, a description, an example or two, and declare options. You are customizing the program's attributes as a whole.*

* This is true for multi-command applications, too, up until your first prog.command() call!


Let's reconstruct sirv-cli, which is a single-command application that (optionally) accepts a directory from which to serve files. It also offers a slew of option flags:

sade('sirv [dir]', true)
  .describe('Run a static file server')
  .example('public -qeim 31536000')
  .example('--port 8080 --etag')
  .example('my-app --dev')
  .option('-D, --dev', 'Enable "dev" mode')
  .option('-e, --etag', 'Enable "Etag" header')
  // There are a lot...
  .option('-H, --host', 'Hostname to bind', 'localhost')
  .option('-p, --port', 'Port to bind', 5000)
  .action((dir, opts) => {
    // Program handler

When sirv --help is run, the generated help text is trimmed, fully aware that there's only one command in this program:

    Run a static file server

    $ sirv [dir] [options]

    -D, --dev        Enable "dev" mode
    -e, --etag       Enable "Etag" header
    -H, --host       Hostname to bind  (default localhost)
    -p, --port       Port to bind  (default 5000)
    -v, --version    Displays current version
    -h, --help       Displays this message

    $ sirv public -qeim 31536000
    $ sirv --port 8080 --etag
    $ sirv my-app --dev

Command Aliases

Command aliases are alternative names (aliases) for a command. They are often used as shortcuts or as typo relief!

The aliased names do not appear in the general help text.
Instead, they only appear within the Command-specific help text under an "Aliases" section.


  • You cannot assign aliases while in Single Command Mode
  • You cannot call prog.alias() before defining any Commands (via prog.commmand())
  • You, the developer, must keep track of which aliases have already been used and/or exist as Command names


Let's reconstruct the npm install command as a Sade program:

  // ...
  .command('install [package]', 'Install a package', {
    alias: ['i', 'add', 'isntall']
  .option('-P, --save-prod', 'Package will appear in your dependencies.')
  .option('-D, --save-dev', 'Package will appear in your devDependencies.')
  .option('-O, --save-optional', 'Package will appear in your optionalDependencies')
  .option('-E, --save-exact', 'Save exact versions instead of using a semver range operator')
  // ...

When we run npm --help we'll see this general help text:

    $ npm <command> [options]

  Available Commands
    install    Install a package

  For more info, run any command with the `--help` flag
    $ npm install --help

    -v, --version    Displays current version
    -h, --help       Displays this message

When we run npm install --help — or the help flag with any of install's aliases — we'll see this command-specific help text:

    Install a package

    $ npm install [package] [options]

    $ npm i
    $ npm add
    $ npm isntall

    -P, --save-prod        Package will appear in your dependencies.
    -D, --save-dev         Package will appear in your devDependencies.
    -O, --save-optional    Package will appear in your optionalDependencies
    -E, --save-exact       Save exact versions instead of using a semver range operator
    -h, --help             Displays this message


sade(name, isSingle)

Returns: Program

Returns your chainable Sade instance, aka your Program.


Type: String
Required: true

The name of your Program / binary application.


Type: Boolean
Default: name.includes(' ');

If your Program is meant to have only one command.
When true, this simplifies your generated --help output such that:

  • the "root-level help" is your only help text
  • the "root-level help" does not display an Available Commands section
  • the "root-level help" does not inject $ name <command> into the Usage section
  • the "root-level help" does not display For more info, run any command with the --help flag text

You may customize the Usage of your command by modifying the name argument directly.
Please read Single Command Mode for an example and more information.

Important: Whenever name includes a custom usage, then isSingle is automatically assumed and enforced!

prog.command(usage, desc, opts)

Create a new Command for your Program. This changes the current state of your Program.

All configuration methods (prog.describe, prog.action, etc) will apply to this Command until another Command has been created!


Type: String

The usage pattern for your current Command. This will be included in the general or command-specific --help output.

Required arguments are wrapped with < and > characters; for example, <foo> and <bar>.

Optional arguments are wrapped with [ and ] characters; for example, [foo] and [bar].

All arguments are positionally important, which means they are passed to your current Command's handler function in the order that they were defined.

When optional arguments are defined but don't receive a value, their positionally-equivalent function parameter will be undefined.

Important: You must define & expect required arguments before optional arguments!


  .command('greet <adjective> <noun>')
  .action((adjective, noun, opts) => {
    console.log(`Hello, ${adjective} ${noun}!`);

  .command('drive <vehicle> [color] [speed]')
  .action((vehicle, color, speed, opts) => {
    let arr = ['Driving my'];
    arr.push(color ? `${color} ${vehicle}` : vehicle);
    speed && arr.push(`at ${speed}`);
    opts.yolo && arr.push('...YOLO!!');
    let str = arr.join(' ');
$ foo greet beautiful person
# //=> Hello, beautiful person!

$ foo drive car
# //=> Driving my car

$ foo drive car red
# //=> Driving my red card

$ foo drive car blue 100mph --yolo
# //=> Driving my blue car at 100mph ...YOLO!!

Type: String
Default: ''

The Command's description. The value is passed directly to prog.describe.


Type: Object
Default: {}


Type: String|Array

Optionally define one or more aliases for the current Command.
When declared, the opts.alias value is passed directly to the prog.alias method.

// Program A is equivalent to Program B
// ---

const A = sade('bin')
  .command('build', 'My build command', { alias: 'b' })
  .command('watch', 'My watch command', { alias: ['w', 'dev'] });

const B = sade('bin')
  .command('build', 'My build command').alias('b')
  .command('watch', 'My watch command').alias('w', 'dev');

Type: Boolean

Manually set/force the current Command to be the Program's default command. This ensures that the current Command will run if no command was specified.

Important: If you run your Program without a Command and without specifying a default command, your Program will exit with a No command specified error.

const prog = sade('greet');

//=> only runs if :: `$ greet hello`

// $ greet
//=> error: No command specified.

prog.command('howdy', '', { default:true });
//=> runs as `$ greet` OR `$ greet howdy`

// $ greet
//=> runs 'howdy' handler

// $ greet foobar
//=> error: Invalid command


Add a description to the current Command.


Type: String|Array

The description text for the current Command. This will be included in the general or command-specific --help output.

Internally, your description will be separated into an Array of sentences.

For general --help output, only the first sentence will be displayed. However, all sentences will be printed for command-specific --help text.

Note: Pass an Array if you don't want internal assumptions. However, the first item is always displayed in general help, so it's recommended to keep it short.


Define one or more aliases for the current Command.

Important: An error will be thrown if:
1) the program is in Single Command Mode; or
2) prog.alias is called before any prog.command.


Type: String

The list of alternative names (aliases) for the current Command.
For example, you may want to define shortcuts and/or common typos for the Command's full name.

Important: Sade does not check if the incoming names are already in use by other Commands or their aliases.
During conflicts, the Command with the same name is given priority, otherwise the first Command (according to Program order) with name as an alias is chosen.

The prog.alias() is append-only, so calling it multiple times within a Command context will keep all aliases, including those initially passed via opts.alias.

  .command('hello <name>', 'Greet someone by their name', {
    alias: ['hey', 'yo']
  .alias('hi', 'howdy')
  .alias('hola', 'oi');
//=> hello aliases: hey, yo, hi, howdy, hola, oi


Attach a callback to the current Command.


Type: Function

The function to run when the current Command is executed.

Its parameters are based (positionally) on your Command's usage definition.

All options, flags, and extra/unknown values are included as the last parameter.

Note: Optional arguments are also passed as parameters & may be undefined!

  .command('cp <src> <dest>')
  .option('-f, --force', 'Overwrite without confirmation')
  .option('-c, --clone-dir', 'Copy files to additional directory')
  .option('-v, --verbose', 'Enable verbose output')
  .action((src, dest, opts) => {
    console.log(`Copying files from ${src} --> ${dest}`);
    opts.c && console.log(`ALSO copying files from ${src} --> ${opts['clone-dir']}`);
    console.log('My options:', opts);

// $ foo cp original my-copy -v
//=> Copying files from original --> my-copy
//=> My options: { _:[], v:true, verbose:true }

// $ foo cp original my-copy --clone-dir my-backup
//=> Copying files from original --> my-copy
//=> ALSO copying files from original --> my-backup
//=> My options: { _:[], c:'my-backup', 'clone-dir':'my-backup' }


Add an example for the current Command.


Type: String

The example string to add. This will be included in the general or command-specific --help output.

Note: Your example's str will be prefixed with your Program's name.

prog.option(flags, desc, value)

Add an Option to the current Command.


Type: String

The Option's flags, which may optionally include an alias.

You may use a comma (,) or a space ( ) to separate the flags.

Note: The short & long flags can be declared in any order. However, the alias will always be displayed first.

Important: If using hyphenated flag names, they will be accessible as declared within your action() handler!

prog.option('--global'); // no alias
prog.option('-g, --global'); // alias first, comma
prog.option('--global -g'); // alias last, space
// etc...

Type: String

The description for the Option.


Type: String

The default value for the Option.

Flags and aliases, if parsed, are true by default. See mri for more info.

Note: You probably only want to define a default value if you're expecting a String or Number value type.

If you do pass a String or Number value type, your flag value will be casted to the same type. See mri#options.default for info~!


The --version and -v flags will automatically output the Program version.


Type: String
Default: 0.0.0

The new version number for your Program.

Note: Your Program version is 0.0.0 until you change it.

prog.parse(arr, opts)

Parse a set of CLI arguments.


Type: Array

Your Program's process.argv input.

Important: Do not .slice(2)! Doing so will break parsing~!


Type: Object
Default: {}

Additional process.argv parsing config. See mri's options for details.

Important: These values override any internal values!

  .option('-f, --force', 'My flag');
//=> currently has alias pair: f <--> force

prog.parse(process.argv, {
  alias: {
    f: ['foo', 'fizz']
  default: {
    abc: 123
//=> ADDS alias pair: f <--> foo
//=> REMOVES alias pair: f <--> force
//=> ADDS alias pair: f <--> fizz
//=> ADDS default: abc -> 123 (number)

Type: Function
Default: undefined

Callback to run when an unspecified option flag has been found. This is passed directly to mri.

Your handler will receive the unknown flag (string) as its only argument.
You may return a string, which will be used as a custom error message. Otherwise, a default message is displayed.

  .command('start [dir]')
  .parse(process.argv, {
    unknown: arg => `Custom error message: ${arg}`

$ sirv start --foobar

    Custom error message: --foobar

  Run `$ sirv --help` for more info.

Type: Boolean
Default: false

If true, Sade will not immediately execute the action handler. Instead, parse() will return an object of { name, args, handler } shape, wherein the name is the command name, args is all arguments that would be passed to the action handler, and handler is the function itself.

From this, you may choose when to run the handler function. You also have the option to further modify the args for any reason, if needed.

let { name, args, handler } = prog.parse(process.argv, { lazy:true });
console.log('> Received command: ', name);

// later on...
handler.apply(null, args);

Manually display the help text for a given command. If no command name is provided, the general/global help is printed.

Your general and command-specific help text is automatically attached to the --help and -h flags.

Note: You don't have to call this directly! It's automatically run when you bin --help


Type: String
Default: null

The name of the command for which to display help. Otherwise displays the general help.


MIT © Luke Edwards



Package last updated on 06 Jan 2022

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