How to pass unknown additional parameters to callback function when invoked?

Question

Invokes func after wait milliseconds. Any additional arguments are provided to func when it is invoked.

I can't think of a good way to pass undefined amount of additional arguments into the callback function. Any suggestion?

function delay(func, wait) {
    return setTimeout(func, wait);
}
// func will run after wait millisec delay

// Example
delay(hello, 100);
delay(hello, 100, 'joe', 'mary'); // 'joe' and 'mary' will be passed to hello function

Possible duplicate of [Is it possible to send a variable number of arguments to a JavaScript function?](https://stackoverflow.com/questions/1959040/is-it-possible-to-send-a-variable-number-of-arguments-to-a-javascript-function) — Joey Pinto, Jan 05 '19 at 00:41

score 3 · Answer 1 · answered Jan 05 '19 at 00:51

3

Define delay like this

function delay(fn, ms) {
  var args = [].slice.call(arguments, 2);

  return setTimeout(function() {
    func.apply(Object.create(null), args);
  }, ms);
}

Or if you are an ES6/7 fan

function delay(fn, ms, ...args) {
  return setTimeout(function() {
    func.apply(Object.create(null), args);
  }, ms);
}

answered Jan 05 '19 at 00:51

Dev Yego

539
2
12

Only w/ `Object.create(null)`, it worked. What's the difference between with and without it? – DatCra Jan 05 '19 at 01:00
Why `Object.create(null)` instead of just `null`? – ic3b3rg Jan 05 '19 at 01:00
I just think it's a safer way to avoid Global object pollution, any can do though. – Dev Yego Jan 05 '19 at 01:02
How is `null` a global? – ic3b3rg Jan 05 '19 at 01:03
I didn't say it's a global, I just said it's my safest way to avoid Global object pollution. If you know the issue of working with `this` and `Function#call()` and `Function#apply()` – Dev Yego Jan 05 '19 at 01:10
oh, I see... you're guarding against `this` being `window` within the scope of `func` - probably overkill in this scenario, but a less verbose way to achieve the same thing would be to use `{}` – ic3b3rg Jan 05 '19 at 01:26
Haha, I know. Better safe than sorry. – Dev Yego Jan 05 '19 at 01:30

How to pass unknown additional parameters to callback function when invoked?

1 Answers1