@csllc/j1939/test/offline/bus-mock.js

J1939 transport layer for CANBUS communication

const J1939 = require('../..');

const { Duplex } = require('stream');

/**
 * Class definition for a mock bus that just cross-connects the transmit and
 * receive, with a configurable delay and some other levers you can pull to
 * create error conditions
 *
 * @class      Bus (name)
 */
class Bus extends Duplex {

  constructor(options) {
    super({ objectMode: true });

    this.options = options;
    this.bOpen = false;
  }

  // required functions for a readable stream, we don't need to do anything
  _read() {}

  // required functions for a writable stream, we don't need to do anything
  _write() {}

  // Error out any requests we are waiting for
  _flushRequestQueue() {}

  isOpen() {
    return this.bOpen;
  }

  // open the port. In this case, cross-connect the objects so sending from
  // one causes a receipt by the other
  open(port) {
    let me = this;
    me.bOpen = true;

    port.on('write', function(data) {

      // console.log('incoming data', data);

      setTimeout(function() {
        me.push(data);
      }, me.options.delay);
    });

    me.emit('open');
  }

  close() {
    this.emit('close');
  }

  write(msg) {
    this.emit('write', msg);
  }
}


module.exports = class J1939Mock extends J1939 {
  constructor(options) {

    let remote = new Bus({ delay: 5 });
    super(remote, options);

    this.local = new Bus({ delay: 5 });
    this.remote = remote;

    // this.local.on('data', function(data) {
    //   console.log('local data:', data);
    // })

  }

  localBus() {
    return this.local;
  }

  openBus() {
    this.openLocal();
    this.openRemote();
  }

  openLocal() {
    this.local.open(this.remote);
  }

  openRemote() {
    this.remote.open(this.local);
  }

};