Getting Started

There are two ways to use the Node-RED Function Extractor:

1. Web Interface (what you're using now)
2. Command Line Tool

Both methods require a Node-RED flow file in JSON format as input.

Usage Examples

Here's an example of what the tool does:

{
  "id": "a1b2c3d4e5f6",
  "type": "function",
  "z": "main_flow_tab",
  "name": "Calculate Temperature Average",
  "func": "const readings = msg.payload;\nif (!Array.isArray(readings)) {\n    node.error(\"Expected array of temperature readings\");\n    return null;\n}\n\nconst sum = readings.reduce((total, val) => total + val, 0);\nconst avg = sum / readings.length;\n\nmsg.payload = {\n    average: avg,\n    count: readings.length\n};\n\nreturn msg;",
  "outputs": 1,
  "noerr": 0,
  "initialize": "",
  "finalize": "",
  "libs": [],
  "x": 380,
  "y": 240,
  "wires": [
    ["temperatureDisplay", "temperatureLogger"]
  ]
}

/**
 * Calculate Temperature Average
 * 
 * Node ID: a1b2c3d4e5f6
 * Flow: main_flow_tab
 * 
 * Connections:
 * ├─ Input: Sensor Reading Node
 * └─ Output:
 *    ├─ temperatureDisplay
 *    └─ temperatureLogger
 * 
 * @param {Object} msg - The message object containing the payload
 * @param {Array} msg.payload - Array of temperature readings
 * @returns {Object} msg - The message with calculated average
 */
function calculateTemperatureAverage(msg) {
    const readings = msg.payload;
    if (!Array.isArray(readings)) {
        throw new Error("Expected array of temperature readings");
    }

    const sum = readings.reduce((total, val) => total + val, 0);
    const avg = sum / readings.length;

    msg.payload = {
        average: avg,
        count: readings.length
    };

    return msg;
}

As shown above, the tool converts function nodes from your Node-RED flow JSON into clean, reusable JavaScript functions with detailed comments documenting node connections and metadata.

Command Line Usage

The tool can be used from the command line with the following options:

node index.js [options]

Options:
  -r, --read <file>     Specify input flow JSON file(s)
  -t, --target <file>   Specify output JavaScript file
  -v, --verbose         Enable verbose output
  -h, --help            Show help

Example command:

node index.js -r flows.json -t extracted_functions.js

Web Interface

The web interface provides a simple way to upload your Node-RED flow file and get the extracted functions:

Basic Usage

1. Navigate to the home page
2. Use the file uploader to select your flow JSON file
3. Click "Extract Functions"
4. The tool will process the file and automatically start a download of the extracted functions

Advanced Features

Our web interface now offers several advanced options:

Output Format

Simple Extraction Format

When using simple extraction, the output is a JavaScript file containing:

• A header with source information and extraction timestamp
• All extracted functions with proper JSDoc comments
• Detailed connection information showing how nodes are wired together
• Dependencies between functions are maintained

Function names are derived from the Node-RED node names, converted to camelCase if necessary.

Structured Extraction Format

When using structured extraction, the output is a ZIP file containing:

• A directory structure that mirrors your Node-RED flow organization
• Individual JavaScript files for each function node
• HTML and CSS files for each template node
• Metadata files with information about the original flow
• A README file explaining the contents

This format is ideal for larger projects or when you want to maintain the organizational structure of your flows.

Advanced Options

When using the command line version, additional options are available:

• Process multiple flow files at once
• Specify custom output locations
• Enable verbose logging

For more details, run node index.js --help

Frequently Asked Questions