How to Swap Two Variables in JavaScript?

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Sometimes in our JavaScript code, we’ve to swap the values of 2 variables in our code.

In this article, we’ll look at ways to swap 2 variables’ values in JavaScript.

One way to swap the value of 2 variables is to use the destructuring syntax.

For instance, we can write:

let a = 5,
  b = 6;
[a, b] = [b, a];
console.log(a, b);

We defined the a and b values which are 5 and 6 respectively.

Then in the 3rd line, we use the destructuring to swap their values.

On the right side, we put b and a into an array.

Then on the right side, we destructure the array entries by putting a and b on .the array on the left side.

So a is 6 and b is 5 when we long the values of a and b on the last line.

We can also use a temporary variable to help swap the values of 2 variables.

To use it, we write:

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

We defined a and b which are 1 and 2 respectively.

Next, we assign a to the tmp temporary variable.

Then we assign b to a .

And finally, we assign the tmp to b to update b with the previous value of a .

Therefore, a is now 2 and b is 1.

We can swap the value of 2 variables with JavaScript by using the restructuring syntax or using a temporary variable.

By John Au-Yeung