@bencevans/ve.direct/parser.js

Victron VE.Direct Parser

const { Transform } = require("stream");

const checksum = (blockBuffer) => {
  return blockBuffer.reduce((prev, curr) => {
    return (prev + curr) & 255;
  }, 0);
};

const parseValues = (frame) => {
  for (let key in frame) {
    switch (key) {
      case "V":
      case "V2":
      case "V3":
      case "VS":
      case "VM":
      case "DM":
      case "VPV":
      case "PPV":
      case "I":
      case "I2":
      case "I3":
      case "IL":
      case "P":
      case "CE":
      case "SOC":
      case "TTG":
      case "AR":
      case "OR":
      case "H1":
      case "H2":
      case "H3":
      case "H4":
      case "H5":
      case "H6":
      case "H7":
      case "H8":
      case "H9":
      case "H10":
      case "H11":
      case "H12":
      case "H13":
      case "H14":
      case "H15":
      case "H16":
      case "H17":
      case "H18":
      case "H19":
      case "H20":
      case "H21":
      case "H22":
      case "H23":
      case "ERR":
      case "CS":
      case "BMV":
      case "FW":
      case "FWE":
      case "PID":
      case "HSDS":
      case "MODE":
      case "AC_OUT_V":
      case "AC_OUT_I":
      case "AC_OUT_S":
      case "WARN":
      case "MPPT":
        frame[key] = parseInt(frame[key]);
        break;

      default:
        frame[key] = frame[key];

        break;
    }
  }

  return frame;
};

class VEDirectParser extends Transform {
  constructor() {
    super({
      readableObjectMode: true,
    });

    this.buf = Buffer.alloc(0);
    this.blk = {};
  }

  _transform(chunk, _, cb) {
    const [key, val] = chunk.toString().split("\t");

    if (key[0] === ":") {
      return cb();
    }

    this.buf = Buffer.concat([this.buf, Buffer.from([0x0d, 0x0a]), chunk]);

    if (key === "Checksum") {
      if (checksum(this.buf) === 0) {
        this.push(parseValues(this.blk));
      }

      this.buf = Buffer.alloc(0);
      this.blk = {};
    } else {
      this.blk[key] = val;
    }

    cb();
  }
}

module.exports = VEDirectParser;
module.exports.checksum = checksum;