counterNode.md

Counter (counterNode)

Category: Control Flow

Intended behavior

Increments/decrements a count on trigger signal.

Inputs

ID	Label	Type	Unwired default
incTrigger	Inc	trigger	undefined
decTrigger	Dec	trigger	undefined
resetTrigger	Reset	trigger	undefined

Outputs

ID	Label	Type	Default
count	Count	number	undefined

Configuration defaults

{
  "count": 0
}

Observed frontend behavior

This calls the production passive computation with the declared input/config defaults. Cached state, trigger execution and project wiring are separate.

{
  "kind": "passive-default-probe",
  "outputs": {
    "count": 0
  }
}

Observed backend behavior

Offline production passive computation with the same declared defaults; no device or model service is invoked.

{
  "kind": "passive-default-probe",
  "outputs": {}
}

Current frontend implementation

Extracted production branches; helper calls and project execution context are defined in the referenced modules.

src/lib/execution-helpers.ts:242

case "counterNode":
      outputs.count = Number(config.count ?? 0);
      break;

src/lib/execution-helpers.ts:415

if (type === "counterNode") {
    let change = 0;
    if (targetPortId === "incTrigger") change = 1;
    else if (targetPortId === "decTrigger") change = -1;

    // safeNum: a count that ever became non-numeric (stale saved file,
    // hand-edited config) would otherwise turn NaN and wedge the counter
    // forever — NaN + 1 is NaN, so no later trigger could recover it.
    const currentCount =
      targetPortId === "resetTrigger"
        ? 0
        : safeNum(config.count) + change;

    updatedConfig = { ...config, count: currentCount };
  }

Implementation references

• src/lib/execution-helpers.ts:242
• src/lib/device-node-compute.ts:52
• src/lib/extra-trigger-ops.ts:18
• backend/engine/trigger_state.py:35

Verification limits

• Default passive probe is an observation, not proof of all configurations, trigger behavior, or correctness. See ../NODE_RUNTIME_AUDIT.md and ../AUDIT_VALIDATION.md for test evidence.
• Trigger inputs schedule actions; passive evaluation alone does not execute those actions. Wire a trigger source and test the full chain.

Source fingerprint: 7e9d192bd3a559a7c50253919867601ef02c311d61e859f7afb4cadcfa508430. Rebuild with npm run docs:index.