commander.js : how to specify required cli argument

Question

I'm using commander.js package for parsing command-line arguments: I'd like to make a flag non-optional, the API and tests in the git repo loosely mention making a flag required, but I usually need to be hit over the head with instructions.

Is it actually possible, and will the script throw if the requirement is not met?

Alevin

Answer 1

I guess this is not supported by commander.js https://github.com/visionmedia/commander.js/issues/44

But you can do something like this in your program -

if (!program.myoption) 
  throw new Error('--myoption required')

Tupungato

commander has program.requiredOption() to flag an option as required now. – Euthanasia

Answer 2

It depends on how you write the arguments.

• With <> it is required.
• With [] it is not required.

See exemple.

const commander = require('commander')
    , program = new commander.Command()

program
   .command('autorecord')
   .argument('<title>', 'Title and file name of record') // is required
   .argument('[type]', 'Type of record. "undefined" by default') // is not required

Alvera

Answer 3

2024 makeOptionMandatory

Per Commander 11.1+

const csv = new Option('--csv <name...>', 'CSV to read from').makeOptionMandatory()
p.command(...).addOption(csv)

... https://www.jsdocs.io/package/commander#Option.makeOptionMandatory

Urbina

Answer 4

From Commander v4 you can use command.requiredOption(): https://github.com/tj/commander.js#required-option

Or as in another answer you can make an Option object and use option.makeOptionMandatory() and command.addOption().

Olsewski