Null safe usage

Using property references that might be null in expressions can lead to unexpected results. This topic contains examples and how to handle them.

The examples in this topic use the following data model:

{
  "user": {
    "name": {
      "given": "John",
      "family": "Doe"
    }
}

String concatenation

Issue: Because user.name.middle is null, the expression user.name.given + ', ' + user.name.middle + ', ' + user.name.family returns John, null, Doe.
Solution to concatenate only non-null values: #string.join({user.name.given, user.name.middle, user.name.family}, ', ') returns John, Doe.
Issue: Because user.age is null and the other operand is numeric, the expression 3 + user.age returns an error.
Solution to avoid errors using an Elvis operator to add a default value: 3 + (user.age ?: '') returns 3.

Issue: The newly created array {user.externalId} returns [ null ].
Solution to remove nulls from the newly created array: #data.removeAll({user.externalId}, {null}) returns [].

Issue: Because user.enabled is null, the expression user.enabled ? 'Active' : 'Inactive' returns an error.
Solution to avoid errors using an Elvis operator to add a default value: (user.enabled ?: false) ? 'Active' : 'Inactive' returns Inactive.