Swap two variables

There are a few ways to swap two variables without using a temporary variable:

[a, b] = [b, a];

// Or
a = [b, (b = a)][0];

// Or
a = ((x) => x)(b, (b = a));

If both variables are numbers, then you can swap them with operators:

a = b + ((b = a), 0);

// Or
a = b * ((b = a), 1);