Serial

Convenience wrapper on top of serialport for Node.js, providing the following features:

• Automatic connection healing
• Connection naming
• Easy event management
• Asynchronous send methods

Contents

• Requirements
• Installation
• Examples
• API Docs
• License

Requirements

• Node 14+

Installation

npm install @appliedminds/serial

Usage / Examples

Create a new Device for any piece of hardware that uses serial to communicate.

For example, imagine a motor board that uses F, B or S to send forward, back or stop commands, respectively:

import { Device as SerialDevice } from '@appliedminds/serial'

class Motor {
    constructor(port) {
        this.device = new SerialDevice({ name: 'motor', port, baudRate: 57600, autoConnect: false })
        this.device.on('data', this.onReceive.bind(this))
        this.device.connect()
        this.state = 'stopped'
    }
    backward() {
        this.device.send('B')
    }
    forward() {
        this.device.send('F')
    }
    onReceive(data) {
        // Cache state when the device relays its state
        this.state = data
    }
    stop() {
        this.device.send('S')
    }
}

const myMotor = new Motor('COM3')
myMotor.forward()

Another example would be a power controller that sends a number representing which button has been pressed:

import EventEmitter from 'events'
import SerialDevice from '@appliedminds/serial'

class PowerControl extends EventEmitter {
    constructor(port) {
        super()
        this.device = new SerialDevice({ name: 'powerControls', port })
        this.device.on('data', this.onReceive.bind(this))
    }
    onReceive(data) {
        let buttons = {0: 'power', 1: 'standby', 2: 'aux'}
        this.emit(buttons[data])
    }
}

const powerControls = new PowerControls('/dev/cu.usbmodem1337')

powerControls.on('power', () => {
    console.log('Power button pressed')
})

powerControls.on('aux', () => {
    console.log('Aux button pressed')
})

API Docs

new Device({ name : String, port : String, baudRate? : Number, reconnectInterval? : Number, autoConnect? : Boolean, parser? : Transform })

Constructor

• name: Human-readable identifier for logging/errors
• port: Qualified path on MacOS/Linux (/dev/some/device/path) or COM port on Windows (COM3)
• baudRate: Baud rate used for communication (default: 115200)
• reconnectInterval: Seconds until reconnect attempt after disconnect or error (default: 3)
• autoConnect: Automatically connect on instantiation (default true). If you set this to false, you'll need to manually call connect() at a later time.
• parser: Which parser to use for incoming data (defaults to @serialport/parser-readline, a parser that splits on newlines). Other parsers can be found at @serialport, or you can write your own Stream.Transform.

Event: 'close'

Emitted when a connection is closed, either expectedly or unexpectedly

Event: 'connect'

Emitted when a successful connection has been made.

Event: 'data'

Emitted with a Buffer when data is received for this device. If no parser is specified, this will be called once per line.

device.close() : <Promise>

Manually close connection. Resolves once the connection has been closed.

device.connect() : <Promise>

Connect to device. The returned promise will resolve once connected.

device.send(data : Buffer/String) : <Promise>

Send serial data to device. Resolves once data is sent.

• data: Outgoing Buffer or string

Contributing & Tests

1. Install development dependencies: npm install
2. Run test suite: npm test

License

MIT