Set Variable

Writes one named app-wide variable when its Do signal fires, converting the value per the 'Set as' type choice.

Set Variable stores a value into the named app-wide variable — the same store Variable2 reads — only when the do (Do) signal fires; the incoming value is held but nothing is written before that. setWith (Set as, parameters-only) selects the value type: it types the node's dynamic value input and controls conversion on store — 'boolean' coerces with !!, 'emptyString' writes '' and removes the value input entirely, and 'object'/'array' accept a shared Object/Array id string and resolve it to the actual object or collection before storing. Writes always use force-change semantics, so Variable2 nodes bound to that name fire changed even when the new value equals the old one. done fires after the store completes, failure when no name is set, and completed after either.

When to use it

Use it when writing shared state should happen at an explicit moment — on click, on submit, after a fetch — or when you need the type conversions ('Set as'). For continuous write-on-change semantics, wire into a Variable2 node's value input instead; to clear a variable, choose Set as 'Empty string'.

At a glance

Category	Data
Type name	Set Variable
Available in	browser, cloud
SSR compatibility	safe
Provided by	noodl-runtime

Inputs

Values

Name	Type	Default	Description
name	String (VariableName id)	—	Which app-wide variable to write; leaving it blank refuses the write rather than storing it somewhere unreadable
setWith	Enum (string, boolean, number, emptyString, date, object, array, *)	*	Chooses the type of the Value port; Empty string stores "" and needs no Value, Object and Array accept an id as well as a value, and Boolean is coerced

Signals

Name	Type	Default	Description
do	Signal	—	Writes Value into the named variable, or fires Failure when no Name is set

Outputs

Signals

Name	Type	Default	Description
completed	Signal	—	Fires after every invocation, whatever the outcome — wire this to carry on regardless. Failure still fires and still carries its reason, so this cannot hide an error
done	Signal	—	Fires once the variable has been written and every Variable node reading it has been notified

Failure outputs

Name	Type	Default	Description
error	String	—	Why the write was refused, in one sentence; empty until something fails
failure	Signal	—	Fires when nothing was stored because no variable Name is set

Dynamic ports

This node's port list changes at runtime (runtime-discovered); the tables above may be incomplete for a given instance.

The value input type follows the selected variable type.

Ports at runtime

The value input is runtime-determined: the editor pushes a single dynamic input port named value whose type follows the setWith parameter ('*' when unset), and no value port exists at all when setWith is 'emptyString'. The runtime registers value on demand when a connection or parameter references it. An authoring tool may wire or set value (except in emptyString mode) and must set setWith via parameters, never a connection.

Patterns

• Button onClick → do with the form's data on value: commit shared state at the moment of a user action.
• done → a navigation or feedback signal: sequence 'store, then move on' explicitly.

Watch out for

• Expecting the write to happen when value changes — Set Variable only writes on do. Use Variable2's value input for write-on-change.

Examples

Share a value between components with Set Variable and Variable

The idiomatic shared-state shape, contrasting per-instance and app-wide storage. In the form component, a String node snapshots the text field: because its saveValue (Set) is connected, keystrokes only latch a pending value, and the Button click commits it. The String's stored signal then fires the Set Variable's do, writing the committed text into the app-wide variable 'userName' (setWith 'string' types the dynamic value input). In a completely separate component, a Variable2 node bound to the same name reads the value reactively — its changed/value update the greeting automatically whenever the variable is written, with no connection between the two components.

Related nodes

Variable, Object, String, Boolean, Number

Generated

This page is generated from node-catalog-enriched.json. Do not edit it by hand — run npm run docs:nodes to regenerate, and fix the source enrichment instead.