Swap Two Numbers in JavaScript

Temp variable, then destructuring. The second one is the one you keep.

BeginnerBasic ProgramsExample 5 of 10

swap-two-numbers.js

1// Method 1: Using a temporary variable
2let a = 5;
3let b = 10;
4console.log("Before swap: a =", a, ", b =", b);
5
6let temp = a;
7a = b;
8b = temp;
9console.log("After swap: a =", a, ", b =", b);
10
11// Method 2: Using destructuring (ES6 - Modern approach)
12let x = 5;
13let y = 10;
14console.log("Before swap: x =", x, ", y =", y);
15
16[x, y] = [y, x];
17console.log("After swap: x =", x, ", y =", y);
18
19// Method 3: Using arithmetic (without temp variable)
20let p = 5;
21let q = 10;
22console.log("Before swap: p =", p, ", q =", q);
23
24p = p + q;
25q = p - q;
26p = p - q;
27console.log("After swap: p =", p, ", q =", q);

Output

Before swap: a = 5 , b = 10
After swap: a = 10 , b = 5
Before swap: x = 5 , y = 10
After swap: x = 10 , y = 5
Before swap: p = 5 , q = 10
After swap: p = 10 , q = 5

What's going on

Temp swap: three lines, easy to mess up.

[a, b] = [b, a] is the JS version. Right-hand side builds an array first. No temp.

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