Identity function

Return the argument unchanged.

JavaScript Version 1.0.0 · MIT · .md

function identity(value) { return value; }

Input & expected output

{
  "id": "msg_123",
  "status": "queued"
}

{
  "id": "msg_123",
  "status": "queued"
}

The edge case

null

null

Know the limits

• Useful as a default transform: a pipeline step that does nothing, or values.filter(identity) to keep truthy items.
• It returns the same reference; it does not copy objects.

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

• Logical xor operator — True when exactly one of two values is truthy.
• Box handler — Chain transformations on a value, then unwrap the result.
• Check if a value is a function — True for anything callable: functions, arrows, async and generator functions, classes.