3.12`default`

This is incredibly useful.

Input:

{
  "name": "Acme"
}

There is no phone number.

This:

payload.phone

could produce null/missing-data behavior depending on the expression and input.

Frequently you use:

payload.phone default "Unknown"

Example:

{
    Name: payload.companyName,
    Phone: payload.phone default "N/A"
}

Input:

{
  "companyName": "Acme"
}

Output:

{
  "Name": "Acme",
  "Phone": "N/A"
}

Conceptually:

payload.phone ?? "N/A"