Promisified variadic function

gistfile1.txt

> function foo(arg1, arg2, arg3) {
    if (arguments.length === 2) {
      arg3 = arg2
    }
    console.log('arg1', arg1)
    console.log('arg2', arg2)
    console.log('arg3', arg3)
  }
undefined
> foo(1, 2, 3)
arg1 1
arg2 2
arg3 3
undefined
> const {promisify} = require('util')
undefined
> promisify
{ [Function: promisify] custom: Symbol(util.promisify.custom) }
> const thing = promisify(foo)
undefined
> thing(1, 2, 3)
arg1 1
arg2 2
arg3 3
Promise {
  <pending>,
  domain:
   Domain {
     domain: null,
     _events: { error: [Function: debugDomainError] },
     _eventsCount: 1,
     _maxListeners: undefined,
     members: [] } }
> thing(1, 2)
arg1 1
arg2 2
arg3 (err, ...values) => {
        if (err) {
          promiseReject(promise, err);
        } else if (argumentNames !== undefined && values.length > 1) {
          const obj = {};
          for (var i = 0; i < argumentNames.length; i++)
            obj[argumentNames[i]] = values[i];
          promiseResolve(promise, obj);
        } else {
          promiseResolve(promise, values[0]);
        }
      }
Promise {
  <pending>,
  domain:
   Domain {
     domain: null,
     _events: { error: [Function: debugDomainError] },
     _eventsCount: 1,
     _maxListeners: undefined,
     members: [] } }
>