Behaviour

Game logic written as a small JavaScript file (params, replicated state, event handlers, kit calls) — run once on the authority peer, with a live node view of its events, state and knobs.

This page is a quick reference for the node. The file format, who runs it and the rules the code must follow are in the full guide: Behaviours.

Output: the sockets its code declares (none by default)

Sockets come from the code

A new Behaviour node has no sockets. They appear when the file declares them:

In the code	On the card	Type
inputs: ['tap']	an input ▸ tap on the left	event — a pulse runs the tap handler in on, on the authority
outputs: ['taps'] where taps is a state field	an output on the right, with the live value beside it	typed by the field's starting value (0 → number)
outputs: ['done'] where done is not a state field	an output marked ⚡	event — fired by this.emit('done')

Change the declaration, save, and the sockets follow. See For module and game authors for the details.

The card

• The behaviour's name and a status dot: running (with its number of handlers), loading, off or error — an error names the line, and code that could not be applied shows a warning.
• Open view — the read-only live node view of its events, handlers, state and knobs.
• Code (or double-click the node) — the file in the code workspace; Ctrl+S reloads it.
• Stop / Run — switches the behaviour off and on; its state is kept.

Parameters

Parameter	Default	Options
name	Behaviour	the name on the card (in the ⓘ Params tab)
enabled	on	the Stop / Run switch; off stops its handlers and removes what it set up, the state is kept
the file's params	from the code	each one is a row in the ⓘ Params tab; editing it rewrites the number in the code

A new node starts with a working example — a countdown that loses the round when it reaches zero — to copy from.

Practical example

Three taps light a lamp:

1. Add a Behaviour node, press Code and replace the file with:

   export default behaviour({
       name: 'Taps',
       state: { taps: 0 },
       inputs: ['tap'],
       outputs: ['taps'],
       on: {
           tap() {
               this.state.taps += 1;
           }
       }
   });
   

   Save with Ctrl+S: the card grows a ▸ tap input and a taps output. 2. Add a Key Press (capture T) and wire it → the Behaviour's tap. 3. Add a Compare (op gte, b = 3) and wire taps → its a. 4. Wire Compare → a Visibility node's on, and Visibility → an Object Selector picking the lamp. 5. Press Play and tap T three times: the count shows on the card and the lamp appears for everyone.

Tip

Logic that is easier to wire than to write — a pulse that should hold, a delay, a one-shot — belongs in nodes such as Latch, Delay and Once. Reach for a Behaviour when the rule has loops, timers that call themselves, or several exceptions.