@tomneutens/serial_monitor
Version:
A web based serial monitor for communicating with serial devices (like Arduino). The library is based on native web components and uses the WebSerial API to communicate with the external device.
115 lines • 4.33 kB
JavaScript
/**
* @author Tom Neutens <tomneutens@gmail.com>
*/
class WebSerialConnection {
constructor() {
this.serialConnected = false;
this.openPort = null;
this.serialDataEventHandlers = new Array();
this.serialDisconnectEventHandlers = new Array();
this.serialConnectEventHandlers = new Array();
this.sendQueue = new Array();
}
addSerialDataEventHandler(handler) {
this.serialDataEventHandlers.push(handler);
}
addSerialDisconnectEventHandler(handler) {
this.serialDisconnectEventHandlers.push(handler);
}
addSerialConnectEventHandler(handler) {
this.serialConnectEventHandlers.push(handler);
}
sendByte(byte) {
this.sendQueue.push(byte);
}
notifyDataHandlers(data) {
this.serialDataEventHandlers.forEach(handler => handler(data));
}
notifyConnectHandlers() {
this.serialConnectEventHandlers.forEach(handler => handler());
}
notifyDisconnectHandlers() {
this.serialDisconnectEventHandlers.forEach(handler => handler());
}
hasWebSerialSupport() {
if ("serial" in navigator) {
return true;
}
else {
window.alert("Webserial not supported by your browser. Consider using chrome or edge.");
return false;
}
}
disconnect() {
this.serialConnected = false;
}
async connect(baudRate, filters = []) {
if (!this.hasWebSerialSupport()) {
return;
}
this.baudRate = baudRate;
let stopped = false;
try {
let port = await navigator.serial.requestPort({ filters: filters });
// asynchronously start listening to port
port.open({ baudRate: this.baudRate }).then(async () => {
this.notifyConnectHandlers();
this.serialConnected = true;
while (port.readable && port.writable && !stopped) {
const reader = port.readable.getReader();
const writer = port.writable.getWriter();
this.openPort = port;
try {
while (true && !stopped) {
const { value, done } = await reader.read();
if (!this.serialConnected || done) {
reader.cancel();
writer.releaseLock();
// |reader| has been canceled.
stopped = true;
}
if (value) {
value.forEach((element) => { this.notifyDataHandlers(element); });
}
if (this.sendQueue.length > 0) {
let nextOnQueue = this.sendQueue.shift();
let data = new Uint8Array([nextOnQueue]);
await writer.write(data);
}
}
}
catch (error) {
// Handle |error|…
this.openPort = null;
this.serialConnected = false;
}
finally {
reader.releaseLock();
this.notifyDisconnectHandlers();
}
}
port.close();
}).catch((error) => {
console.error(error);
});
}
catch (error) {
console.error(error);
this.serialConnected = false;
this.notifyDisconnectHandlers();
}
}
setupWebSerial() {
if (navigator.serial) {
navigator.serial.addEventListener('connect', (e) => {
});
navigator.serial.addEventListener('disconnect', (e) => {
this.notifyDisconnectHandlers();
});
navigator.serial.getPorts().then((ports) => {
});
}
}
}
export default WebSerialConnection;
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