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@abetomo abetomo released this 25 Jun 08:25
· 117 commits to master since this release


  • .argument(name, description) for adding command-arguments (#1490)
    • supports default value for optional command-arguments (#1508)
    • supports custom processing function (#1508)
  • .createArgument() factory method (#1497)
  • .addArgument() (#1490)
  • Argument supports .choices() (#1525)
  • .showHelpAfterError() to display full help or a custom message after an error (#1534)
  • .hook() with support for 'preAction' and 'postAction' callbacks (#1514)
  • client typing of .opts() return type using TypeScript generics (#1539)
  • the number of command-arguments is checked for programs without an action handler (#1502)
  • .getOptionValue() and .setOptionValue() (#1521)


  • refactor and simplify TypeScript declarations (with no default export) (#1520)
  • .parseAsync() is now declared as async (#1513)
  • Breaking: Help method .visibleArguments() returns array of Argument (#1490)
  • Breaking: Commander 8 requires Node.js 12 or higher (#1500)
  • Breaking: CommanderError code commander.invalidOptionArgument renamed commander.invalidArgument (#1508)
  • Breaking: TypeScript declaration for .addTextHelp() callback no longer allows result of undefined, now just string (#1516)
  • refactor into a file per class (#1522)
  • remove help suggestion from "unknown command" error message (see .showHelpAfteError()) (#1534)
  • Command property .arg initialised to empty array (was previously undefined) (#1529)
  • update dependencies


  • second parameter of cmd.description(desc, argDescriptions) for adding argument descriptions (#1490)
    • (use new .argument(name, description) instead)
  • InvalidOptionArgumentError (replaced by InvalidArgumentError) (#1508)


  • Breaking: TypeScript declaration for default export of global Command object (#1520)
    • (still available as named program export)

Migration Tips

If you have a simple program without an action handler, you will now get an error if
there are missing command-arguments.

  .option('-d, --debug')
$ node trivial.js 
error: missing required argument 'file'

If you want to show the help in this situation, you could check the arguments before parsing:

if (process.argv.length === 2);

Or, you might choose to show the help after any user error: