Swap two variables

Exchange two values with array destructuring.

JavaScript Version 1.0.0 · MIT · .md

function swap([a, b]) { [a, b] = [b, a]; return [a, b]; }

Input & expected output

[
  "[email protected]",
  "[email protected]"
]

[
  "[email protected]",
  "[email protected]"
]

The edge case

[
  0,
  null
]

[
  null,
  0
]

Know the limits

• Destructuring works for any values. The original’s arithmetic tricks (a = b + ((b = a), 0)) only work for numbers and are harder to read.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Convert Celsius to Fahrenheit — Apply the temperature conversion without rounding the result.
• Convert hex to RGB — Expand #rgb if needed and read the red, green and blue channels.
• Convert URL parameters to object — Read a query string into an object; repeated keys become arrays.