required resuable flag

flag.js

// flag.js
import { merge, type Flag } from 'cli-engine-command/lib/flags'

type Options = $Shape<Flag<boolean>>
export default function ResetFlag (options: Options = {}, env: typeof process.env = process.env): Flag<string> {
  const defaultOptions: Options = {
    char: 'r',
    parse: (input, cmd) => {
      if (options.required) throw new Error('you should have set --reset')
    }
  }
  return merge(defaultOptions, options)
}

// v6 command

class MyCommand extends Command {
  static flags = {
    reset: flags.reset()
  }

  async run() {
    // guaranteed to have this.flags.reset === true
  }
}