Swapping Variables

Node.js swaps two variables with array destructuring, no temporary variable needed. Go does the exact same thing with multiple assignment — also with no temporary variable. Rust has had destructuring assignment for tuples since 1.59 ((b, a) = (a, b)), the same idea. Swift ships a swap(&a, &b) function in its standard library. Java has no syntax for this at all — you still need a temporary variable.

Swapping two variables

let a = 'foo';
let b = 'bar';
 
console.log(a, b); // foo bar
 
[b, a] = [a, b];
 
console.log(a, b); // bar foo

package main
 
import "fmt"
 
func main() {
	a := "foo"
	b := "bar"
 
	fmt.Println(a, b) // foo bar
 
	b, a = a, b
 
	fmt.Println(a, b) // bar foo
}

fn main() {
    let mut a = "foo";
    let mut b = "bar";
 
    println!("{a} {b}"); // foo bar
 
    (b, a) = (a, b); // destructuring assignment, no `let` needed
 
    println!("{a} {b}"); // bar foo
}

var a = "foo"
var b = "bar"
 
print(a, b) // foo bar
 
swap(&a, &b) // swap ships in the standard library
 
print(a, b) // bar foo

void main() {
    String a = "foo";
    String b = "bar";
 
    IO.println(a + " " + b); // foo bar
 
    // no destructuring assignment: still needs a temporary variable
    String temp = a;
    a = b;
    b = temp;
 
    IO.println(a + " " + b); // bar foo
}