node-red-contrib-keyvalue-r2/nodes/keyvalue-write-r2.js

Node-RED nodes for reading and writing key-value pairs in a JSON file.

const fs = require('fs');
const path = require('path');

module.exports = function (RED) {
  function KeyValueWrite(config) {
    RED.nodes.createNode(this, config);
    const node = this;
    const filePath = config.filePath;

    node.on('input', function (msg) {
      try {
        const key = msg.topic;
        const value = msg.payload;
        let data = {};

        if (fs.existsSync(filePath)) {
          data = JSON.parse(fs.readFileSync(filePath));
        }

        data[key] = value;
        fs.writeFileSync(filePath, JSON.stringify(data, null, 2));
        node.send(msg);
      } catch (error) {
        node.error('Error writing JSON file: ' + error.message);
      }
    });
  }
  RED.nodes.registerType('keyvalue-write', KeyValueWrite);
};