Null
Description
Pure function producing a null on purpose. Wire it into a nullable model field of a Make node, or into a branch of Select boolean, to leave that field empty. When a model is serialized, XML leaves a null field out entirely while JSON and YAML write an explicit null and CSV and Excel write an empty cell. Generic in type and shape: it takes the type of the input it is wired into.
When to use
Use Null when a value should be absent rather than zero or empty. An unwired decimal pin
gets 0, not null, so the only way to leave a nullable model field truly empty is to wire
a Null into it — typically through Select boolean, so the field is set in some cases and
left out in others. What “empty” looks like depends on the output format: XML leaves the
element or attribute out, JSON and YAML write null, and CSV and Excel write an empty
cell. The field must be marked nullable on the model; otherwise the editor warns that a
null can reach a field that does not accept one.
Pins
Output pins
| Pin | Type | Notes |
|---|---|---|
| Value | generic | Always null. The type and shape resolve at design-time from the input it is wired into, so it connects to a decimal, a model or an array alike. A null reaching a field that is not marked nullable is flagged by a warning. |
Example
Leave a fee out of an XML export when there is none. Wire Greater than into the Condition input of Select boolean, wire the fee into When true and a Null node into When false, and wire the Result output into the nullable fee field of a Make node. When the condition is false the field is null, so Model to string with the XML format leaves the element out.