Script Filter

Use this node to evaluate a custom boolean condition against an incoming message. It is the most flexible filter in the rule engine: you write a TBEL or JavaScript function that inspects the message data, metadata, and type, then returns true or false to route the message accordingly.

Configuration

Script language — required. Choose TBEL or JavaScript.
Script body — required. A function that receives three arguments and must return a boolean:
- msg — the message data (object or array).
- metadata — the message metadata. In JavaScript, an object where all values are strings; in TBEL, a java.util.Map<String, String>.
- msgType — the message type as a string.

Message processing algorithm

Select the script to execute based on the configured Script language.
Execute the script function.
Route the message:
- Returns true → True connection.
- Returns false → False connection.
- Throws an exception or returns a non-boolean → Failure connection.

Output connections

Connection	Condition
`True`	The script returned `true`.
`False`	The script returned `false`.
`Failure`	The script returned a non-boolean value, or threw an exception.

Examples

Example 1 — JS threshold check → `True`

Any numeric telemetry value exceeds its corresponding threshold from metadata.

Incoming message

Data:

{
  "temperature": 45.2,
  "humidity": 80,
  "pressure": 1010
}

Metadata:

{
  "temperatureThreshold": "45.0",
  "humidityThreshold": "85"
}

Message type: POST_TELEMETRY_REQUEST

Node configuration

{
  "scriptLang": "JS",
  "jsScript": "if (msgType !== 'POST_TELEMETRY_REQUEST') {\n    return false;\n}\n\nfor (var key in msg) {\n    var thresholdKey = key + 'Threshold';\n    if (typeof msg[key] === 'number' && metadata[thresholdKey] && !isNaN(metadata[thresholdKey])) {\n        if (msg[key] > Number(metadata[thresholdKey])) {\n            return true;\n        }\n    }\n}\n\nreturn false;"
}

Result: routed via True — temperature (45.2) exceeds its threshold (45.0).

Example 2 — TBEL threshold check → `True`

Same logic in TBEL; humidity (88) exceeds its threshold (85).

Incoming message

Data:

{
  "temperature": 42.1,
  "humidity": 88,
  "pressure": 1010
}

Metadata:

{
  "temperatureThreshold": "45.0",
  "humidityThreshold": "85"
}

Node configuration

{
  "scriptLang": "TBEL",
  "tbelScript": "if (msgType != 'POST_TELEMETRY_REQUEST') {\n    return false;\n}\n\nforeach (key: msg.keySet()) {\n    var thresholdKey = key + 'Threshold';\n    if (metadata.containsKey(thresholdKey)) {\n        var value = msg[key];\n        var threshold = parseDouble(metadata[thresholdKey]);\n        if (value > threshold) {\n            return true;\n        }\n    }\n}\n\nreturn false;"
}

Result: routed via True.

Example 3 — JS runtime error → `Failure`

The script expects msg.data.temperature but msg.data is undefined.

{
  "scriptLang": "JS",
  "jsScript": "return msg.data.temperature > 20;"
}

Result: routed via Failure — runtime error accessing undefined.temperature.

Example 4 — TBEL runtime error → `Failure`

Same — msg.data is null in TBEL.

{
  "scriptLang": "TBEL",
  "tbelScript": "return msg.data.temperature > 20;"
}

Result: routed via Failure.

JSON schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "TbJsFilterNodeConfiguration",
  "type": "object",
  "required": ["scriptLang"],
  "properties": {
    "scriptLang": {
      "type": "string",
      "description": "Scripting language used to execute the function.",
      "enum": ["TBEL", "JS"]
    },
    "jsScript": {
      "type": "string",
      "description": "JavaScript function body that must return a boolean. Used when 'scriptLang' is 'JS'."
    },
    "tbelScript": {
      "type": "string",
      "description": "TBEL function body that must return a boolean. Used when 'scriptLang' is 'TBEL'."
    }
  },
  "additionalProperties": false
}

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