Node-RED Truth Table Node

This Node-RED node, truth-table, provides a truth table functionality for evaluating expressions based on input data.

Installation

To use this node, you need to have Node-RED installed. Follow the official Node-RED documentation for installation instructions.

After installing Node-RED, you can install the truth-table node by either using the Node-RED Editor's palette manager or by running the following command in your Node-RED user directory:

npm install node-red-contrib-truth-table

Usage

The truth-table node evaluates expressions based on the input data and generates a result object. The node has the following properties:

• Name: A name for the node (optional).
• Render Options: Specify the labels for different render levels. These labels will be used in their indexed order in the generated truth table.
• Expressions: An array of expressions to evaluate. Each expression consists of a path, stateExp, and issueExp. The path is used to extract a value from the input payload, and the stateExp and issueExp are JSONata expressions used to evaluate the state and issue for the extracted value, respectively. The expressions are defined in the following format: [{ "path": "<path>", "stateExp": "<state expression>", "issueExp": "<issue expression>" }, ...].

The node has one input and two outputs. The input data should be provided to the input of the node. The outputs are generated based on the evaluation result:

• Output 1: Contains the result object, which includes the following properties:

  • render: The render level based on the evaluated expressions (ok, warning, or critical).
  • issues: An array of issues generated from the evaluated expressions.
  • raw_data: The original input data.

• Output 2: Contains an error message if an error occurs during the evaluation process.