Turns `process.argv` into an array-like object with fixed position arguments indexed by number and named arguments indexed by key.

command-line-args.js

/**
 * Simple command line argument parser
 *
 * An instance of Args is an array-like
 * object that contains a list of fixed
 * and named arguments
 *
 * Given command line args of:
 *
 *    node args.js command -a --param=value
 *
 * This code...
 *
 * ```javascript
 * const args = new Args()
 * console.dir(args)
 * ```
 *
 * ...will produce this output:
 *
 * ```
 * Args(2) [
 *   'topic',
 *   'command',
 *   f: true,
 *   l: true,
 *   a: true,
 *   g: true,
 *   param1: 'value1',
 *   param2: true
 * ]
 * ```
 */
export class Args extends Array {

  constructor(
    args = process.argv.slice(2)
  ) {
    super()
    for (let i = 0, al = args.length; i < al; i++) {
      const item = args[i]
      const isNamed = item.startsWith('-')
      const isShortForm = isNamed && item.charAt(1) !== '-'
      if (isNamed) {
        // named
        let key = '', value = true
        for (let j = 0, il = item.length; j < il; j++) {
          const c = item.charAt(j)
          if (!key && c === '-') continue
          if (value === true && c === '=') value = ''
          else if (value === true) key += c
          else value += c
        }
        if (value === true && isShortForm) {
          key.split('').forEach(k => {
            this[k] = value
          })
        } else {
          this[key] = value
        }
      } else {
        // fixed
        this.push(item)
      }
    }
  }
}

if (import.meta.url === `file://${process.argv[1]}`) {
  /**
   * Hint: try running with the following command:
   *
   *    node args.js topic command -flag --param1=value1 --param2
   */
  const args = new Args()
  console.dir(args)
}