Parse command line arguments in nodejs

Usage no npm install needed!

<script type="module">
  import argparce from '';



An easy argument parser for nodejs


npm install --save argparce


const ArgParser = require('argparce');

API Reference

ArgParser.parse(args, options)

  • args <Array> an array of arguments

  • options <Object>

    • args <Array> an array of argument flag definitions
      • <Object>
        • type <string> The data type of the argument.
          • Valid types are 'string', 'integer', 'uinteger', 'float', 'ufloat', 'url'.
          • 'boolean' arguments do not require a following argument and can be called as --arg (which gives the value true) or --arg=false (which gives the value false)
          • all other argument types must be called either as --arg=value or --arg value
        • name <string> The full name of the argument.
          • Example: 'connect-timeout' will create an argument named --connect-timeout
        • short <string> The short name of the argument.
          • Example: 'v' will create a short argument named -v
        • default <Any> The default value of the argument
    • maxStrays <integer> the maximum number of stray (not attached to flags) arguments allowed, or -1 to allow an infinite amount. Default: 0
    • unmappedArgsDefault <string> the default behavior for handling unrecognized argument flags. Default: null
      • null unrecognized flags will cause an error
      • 'stray' unrecognized flags will be added as stray arguments.
      • 'boolean' unrecognized flags will be read as boolean arguments and added to args in the result
      • 'string' unrecognized flags will be read as string arguments (in the form --arg=<string>)
    • stopAtError <boolean> stop parsing when an error is encountered.
    • stopIfTooManyStrays <boolean> stop parsing when a stray is encountered that can't be added due to maxStrays, and doesn't add an error to errors in the result.
    • errorExitCode <integer> An exit code to exit with if errors occur during parsing, or null to not exit. Default: null
  • Returns <Object>

    • args <Object> An object mapping of argument names to their values
    • errors <Array> An array of string messages for errors that occurred during parsing.
    • endIndex <integer> The args index where parsing stopped, or args.length if parsing completed without stopping
    • strays <Array> An array of stray arguments. Stray arguments are command line parameters that didn't match any arguments defined in options.args. Array is empty by default unless options has some non-default values.
    • stopped <boolean> Indicates if parsing was stopped before finishing

Parses the command line arguments with the given options

  • Example:

    Javascript Code:

    // test.js
    var result = ArgParser.parse(process.argv.slice(2), {
        args: [
                type: 'boolean',
                name: 'verbose',
                short: 'v'
                type: 'uinteger',
                name: 'request-timeout',
                default: 10000
                type: 'string',
                name: 'name'
        maxStrays: 2,
        stopAtError: true

    Command Line:

    node test.js --request-timeout=23470 "bing" --verbose "bang" --name "hello world" "bong"


        "args": {
            "request-timeout": 23470,
            "verbose": true,
            "name": "hello world"
        "strays": ["bing", "bang"],
        "errors": ["invalid argument bong"],
        "stopped": true,
        "endIndex": 6

ArgParser.validate(type, value)

  • type The argument type to valid
    • Valid types are 'string', 'integer', 'uinteger', 'float', 'ufloat', 'url'.
  • value The value to validate against the type
  • Returns: The validated value, or null if validation failed

Validate a value against a type.