Argument

Kind: Class

Source: lib/argument.js

Argument defines a positional argument for a Commander command. It stores argument metadata such as the name, default value, parser, allowed choices, and whether the argument is required or optional.

Methods

Where it refuses work

• Argument stops the work with InvalidArgumentError when !this.argChoices.includes(arg).
• Argument stops the work with an early return when previous === this.defaultValue || !Array.isArray(previous).
• Argument stops the work with an early return when this.variadic.

Diagram

mermaid
graph LR
  Command[Command] --> Argument[Argument]
  Argument --> Name[name()]
  Argument --> Default[default()]
  Argument --> Parser[argParser()]
  Argument --> Choices[choices()]
  Argument --> Required[argRequired()]
  Argument --> Optional[argOptional()]
  Parser --> Action[Command action]
  Choices --> Action

Usage

js
import { Argument, Command } from 'commander';

const mode = new Argument('mode')
  .choices(['development', 'production'])
  .argRequired();

const label = new Argument('label')
  .default('local')
  .argOptional();

const program = new Command();

program
  .name('deploy')
  .addArgument(mode)
  .addArgument(label)
  .action((selectedMode, selectedLabel) => {
    console.log(`Deploying ${selectedLabel} in ${selectedMode} mode`);
  });

program.parse();

AI Coding Instructions

• Create Argument instances and register them with a Command using addArgument().
• Use argRequired() or argOptional() to set positional argument behavior when it is not defined by the argument syntax.
• Use choices() for fixed string values; it sets the argument parsing behavior for choice validation.
• Use argParser() when an argument needs value conversion or custom validation, and return the parsed value.
• Treat _collectValue() as internal behavior for collecting repeated values rather than calling it from command code.

Relationships

• IMPORTS → InvalidArgumentError

Used by

2 references from 2 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (2)

• program — index.js:7
• Command — lib/command.js:14