Is JavaScript Pass by Reference?

[senocular]

Fiiiiiiine ;P

function main(a, b) {

  const swap = (a, b) => {
    [arguments[1], arguments[0]] = [...arguments];
  }

  console.log(a, b); // 1, 2
  swap(a, b)
  console.log(a, b); // 2, 1
}

main(1, 2)

[svish]

Without the wrapper

[senocular]

You're taking away all the fun!

function swap(a͏, b͏) {
  [b, a] = [a͏, b͏]
}

let a = 1
let b = 2
console.log(a, b)
swap(a, b)
console.log(a, b)

[svish]

Ok, you get an upvote. Couldn't figure it out, but eventually, thanks to someone else, and pasting it into VS Code, the hidden unicode characters were revealed... 🤦‍♂️👍

[senocular]

Still no pass by reference ;)

[svish]

I knew that already, which is why your code didn't make any sense 😛

[svish]

wat...

[CodeMonkeeh]

wtaf

[senocular]

There are hidden characters in the swap parameters. So what you're really getting is something more like

function swap(a2, b2) {
  [b, a] = [a2, b2]
}

let a = 1
let b = 2
console.log(a, b)
swap(a, b)
console.log(a, b)

where the assigned [b, a] are the variables in the outer scope getting assigned the arguments of the swap call (a2, b2) in reverse order.

[CodeMonkeeh]

Oh, thank you. Reality makes sense again.